<PAGE>   1
                                                                    EXHIBIT 10.8

                SEVENTH AMENDMENT TO LOAN AND SECURITY AGREEMENT


                  This Seventh Amendment to Loan and Security Agreement
("Amendment") is entered into as of June 1, 1999 by and among FOOTHILL CAPITAL
CORPORATION, a California corporation ("Foothill"), on the one hand, and
NATIONAL AMERICAN CORPORATION, a Nevada corporation ("NACO"), THOUSAND TRAILS,
INC., a Delaware corporation ("Trails"), and the other party borrowers signatory
hereto (each, together with NACO and Trails, individually a "Borrower" and
collectively, jointly and severally, "Borrowers"), on the other hand, in light
of the following:


RECITALS

                  FACT ONE: Borrowers, or their predecessors in interest, and
Foothill have previously entered into that certain Loan and Security Agreement,
dated as of July 10, 1996 (as amended and modified, the "Loan Agreement").

                  FACT TWO: Borrowers have requested that Foothill modify the
provisions thereof to, among other things, reduce the minimum interest
chargeable under the Agreement.

                  FACT THREE: Borrowers and Foothill desire to amend the Loan
Agreement as provided for herein.

AGREEMENT

                  NOW, THEREFORE, Borrowers and Foothill hereby amend and
supplement the Loan Agreement as follows:

                  1.       DEFINITIONS. All initially capitalized terms used in
this Amendment shall have the meanings given to them in the Loan Agreement
unless specifically defined herein.

                  2.       AMENDMENT.

                           2.1      Section 1.1 of the Loan Agreement is hereby
amended by deleting the definition of Revolving Maximum Amount and substituting
the following in its place and stead:

         "Revolving Maximum Amount" means Twenty-Eight Million Four Hundred
         Thirty-Five Thousand Dollars ($28,435,000), which such amount is
         permanently reduced to lower amounts by the greater of (y) the sum of
         (1) an amount equal to the aggregate net cash proceeds of all sales of
         Collateral pursuant to Section 5.4 (other than the last paragraph
         thereof), or as otherwise approved by Foothill, which occur after June
         10, 1998; plus (2) 100% of Account collections, once the Term Note has
         been fully secured by cash; or (z) the amount set forth below opposite
         the applicable date of reduction:


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<TABLE>
<S>      <C>             <C>
         6/30/1999       -       $3,544,000

         12/31/1999      -       $7,108,000

         6/30/2000       -       $10,662,000

         12/31/2000      -       $14,216,000

         6/30/2001       -       $17,770,000

         12/31/2001      -       $21,324,000

         6/30/2002       -       $24,878,000

         1/17/2003       -       $28,435,000:
</TABLE>

         Provided, however, there shall be no reductions in the Revolving
         Maximum Amount as called for in provisions (y)(1) and (2) called for
         above for any sales or collections which occur between June 10, 1998
         and the earlier to occur of the following: (i) the completion of the
         purchase by Borrower of the PIK Notes, or (ii) the purchase of the
         stock of AIC, or (iii) March 31, 1999.

                           2.2      Section 3.5(c) of the Loan Agreement is
hereby amended by deleting said provision in its entirety, and substituting the
following in its place and stead;

         "(a)     Minimum Interest. In no event shall the rate of interest
         chargeable hereunder be less than seven percent (7%) per annum. To the
         extent that interest accrued hereunder at the rate set forth herein
         (including the minimum interest rate) would yield less than the
         foregoing minimum amount, the interest rate chargeable hereunder for
         the period in question automatically shall be deemed increased to that
         rate that would result in the minimum amount of interest being accrued
         and payable hereunder."

                           2.3      Section 4.5 of the Loan Agreement is hereby
amended by deleting said provision in its entirety, and substituting the
following in its place and stead;

         "2.4     Early Termination or Paydown by Borrower. Borrower has the
         option, at any time upon thirty (30) days prior written notice to
         Foothill, to terminate this Agreement by paying to Foothill, in cash,
         the Obligations, together with a premium (the "Early Paydown Premium")
         payable in the following events, as follows:

                  (A) if the termination results from a refinancing or
                  recapitalization of any Borrower, or any portion of the funds
                  used to pay-off the Obligations directly or indirectly result
                  from borrowed money, the Early Paydown Premium shall be equal
                  to the greater of: (a) the total interest owing for the
                  immediately preceding six (6) month period; or (b) (i) Five
                  Hundred Thousand Dollars ($500,000) if terminated during
                  calendar year 1999, (ii) Four Hundred Thousand Dollars
                  ($400,000) if terminated during calendar year 2000, (iii)
                  Three Hundred Thousand Dollars ($300,000) if terminated during
                  calendar year 2001, or (iv) Two Hundred Thousand Dollars
                  ($200,000) if terminated during calendar years 2002 or 2003.


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                  (B)      if the termination results from a complete paydown
                  using funds generated from Borrower's business operations, or
                  in connection with a Change of Control, the Early Paydown
                  Premium shall be equal to the greater of: (a) the total
                  interest owing for the immediately preceding six (6) month
                  period; or (b) (i) Two Hundred and Fifty Thousand Dollars
                  ($250,000) if terminated during calendar year 1999, (ii) Two
                  Hundred Thousand Dollars ($200,000) if terminated during
                  calendar year 2000, (iii) One Hundred and Fifty Thousand
                  Dollars ($150,000) if terminated during calendar year 2001, or
                  (iv) One Hundred Thousand Dollars ($100,000) if terminated
                  during calendar years 2002 or 2003."

                           2.4      Section 4.8(b) of the Loan Agreement is
hereby amended by deleting said provision in its entirety, and substituting the
following in its place and stead:

         "(b)     The purchase of the stock of AIC shall occur on or before
         December 31, 1999."

                           2.5      Section 8.13 of the Loan Agreement is hereby
amended by deleting said provision in its entirety, and substituting the
following in its place and stead;

         "8.13    Investments. Directly or indirectly make or acquire any
         beneficial interest in (including stock, partnership interest, or other
         securities of), or make any loan, advance, or capital contribution in
         excess of One Hundred Thousand Dollars ($100,000) in any fiscal year,
         to, any Person not a Borrower, except (i) payments as contemplated by
         the By-Law Amendment referred to in Section 8.11, and (ii) investments
         in Cash Equivalents. Notwithstanding the prior sentence, Thousand
         Trails, Inc. shall be permitted to purchase up to $100,000 worth of
         Thousand Trails, Inc. stock per month at a price which is not greater
         than the market price for such stock on such dates. Provided that
         Borrower has availability under the Revolving Maximum Amount and
         provided that all other conditions under the Loan Agreement have been
         satisfied, Borrower shall be permitted to use the proceeds of Revolving
         Advances to purchase such stock. Borrower shall be able to cumulate the
         $100,000 monthly cap on repurchases of its own stock, so that any
         unused allowed sums can be carried over into successive months, with a
         maximum carryover allowed amount of $500,000. Commencing July 31, 1999,
         the maximum carryover allowed amount shall be increased to $600,000,
         and such maximum amount shall increase by an additional $100,000 each
         successive month-end until the maximum carryover allowed amount equals
         $1,000,000."

                  3.       LIMITED WAIVER WITH RESPECT TO SECTION 8.7. Foothill
hereby waives the negative covenant contained in Section 8.7 solely to the
extent to allow Trails to establish a wholly owned corporation, OWC Acquisition
Corporation, a Delaware corporation, to facilitate Borrower's possible
acquisition of the assets of Outdoor World Corporation, a Pennsylvania
corporation, which is contemplated in accordance with the terms of that certain
letter of intent issued by Foothill to Borrower contemporaneously herewith.

                  4.       REPRESENTATIONS AND WARRANTIES. Borrower hereby
affirms to Foothill that all of Borrower's representations and warranties set
forth in the Loan Agreement are true, complete and accurate in all material
respects as of the date hereof (except to the extent that such representations
and warranties relate solely to an earlier date).


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                  5.       NO DEFAULTS. Borrower hereby affirms to Foothill that
no Event of Default has occurred and is continuing as of the date hereof.

                  6.       CONDITION PRECEDENT. The effectiveness of this
Amendment is expressly conditioned upon receipt by Foothill of an executed copy
of this Amendment and the fulfillment, to the satisfaction of Foothill and
Foothill's counsel, of each of the following conditions precedent:

                           6.1      Each Borrower shall be a corporation in good
standing in the jurisdiction of its incorporation and qualified to do business
in any other jurisdiction where such qualification is required by law.

                           6.2      Borrower shall have paid to Foothill all of
Foothill's out-of-pocket expenses relating to this Amendment, including, but not
limited to, search fees, title search and insurance fees, filing and recording
fees, examination and appraisal fees, internal transaction charges, and
attorneys fees and expenses.

                  7.       LIMITED EFFECT. In the event of a conflict between
the terms and provisions of this Amendment and the terms and provisions of the
Loan Agreement, the terms and provisions of this Amendment shall govern. In all
other respects, the Loan Agreement, as amended and supplemented hereby, shall
remain in full force and effect.

                  8.       WAIVER. The waiver of certain provisions of the Loan
Agreement as provided in this Amendment which, inter alia, allows Trails to
create a wholly owned subsidiary shall constitute a one time waiver only, and
Foothill shall have the right to require strict compliance with all of the
provisions of the Loan Agreement in the future.

                  9.       BROKERS' FEES. Any brokerage commission or finder's
fees payable in connection with the financing arrangement contemplated hereby
will be payable by Borrowers and not by Foothill. Borrowers and Foothill each
represent and warrant to the other that they have not incurred any obligation
for a brokerage commission or a finder's fee. Borrowers hereby indemnify
Foothill and hold Foothill harmless from and against any claim of any broker or
finder arising out of the financing arrangement described above or any
commitment relating thereto.

                  10.      COUNTERPARTS; EFFECTIVENESS. This Amendment may be
executed in any number of counterparts and by different parties on separate
counterparts, each of which when so executed and delivered shall be deemed to be
an original. All such counterparts, taken together, shall constitute but one and
the same Amendment. This Amendment shall become effective upon the execution of
a counterpart of this Amendment by each of the parties hereto.

                  11.      COMPLETE AGREEMENT; NO ORAL MODIFICATIONS. This
Amendment embodies the entire agreement between the parties hereto with respect
to the subject matter hereof and supersedes all prior proposals, negotiations,
or agreements whether written or oral, relating to the subject matter hereof.
This Amendment may not be modified, amended, supplemented, or otherwise changed,
except by a document in writing signed by the parties hereto.

                  IN WITNESS WHEREOF, the parties hereto have executed this
Amendment as of the date first set forth above.


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                                            "FOOTHILL"

                                            FOOTHILL CAPITAL CORPORATION,
                                            a California corporation


                                            By:    /s/ Katy J. Brooks
                                               ---------------------------------
                                            Title: Vice President
                                                   -----------------------------

                                            "BORROWERS"

                                            NATIONAL AMERICAN CORPORATION,
                                            a Nevada corporation

                                            By:    /s/ Walter B. Jaccard
                                               ---------------------------------
                                            Title: Vice President
                                                   -----------------------------



                                            THOUSAND TRAILS, INC.,
                                            a Delaware corporation, f/k/a
                                            USTrails, Inc., a Nevada
                                            corporation, and New Thousand
                                            Trails, Inc., a Delaware corporation


                                            By:    /s/ Walter B. Jaccard
                                               ---------------------------------
                                            Title: Vice President
                                                   -----------------------------

                                            THOUSAND TRAILS (CANADA) INC.,
                                            a British Columbian corporation


                                            By:    /s/ Walter B. Jaccard
                                               ---------------------------------
                                            Title: Vice President
                                                   -----------------------------


                                            TT OFFSHORE, LTD.,
                                            a Virginia corporation


                                            By:    /s/ Walter B. Jaccard
                                               ---------------------------------
                                            Title: Vice President
                                                   -----------------------------


                                            BEECH MOUNTAIN LAKES CORPORATION,
                                            a Pennsylvania corporation


                                            By:    /s/ Walter B. Jaccard
                                               ---------------------------------
                                            Title: Vice President
                                                   -----------------------------


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                                            CAROLINA LANDING CORPORATION,
                                            a South Carolina corporation


                                            By:    /s/ Walter B. Jaccard
                                               ---------------------------------
                                            Title: Vice President
                                                   -----------------------------

                                            CARRIAGE MANOR CORPORATION,
                                            a North Carolina corporation


                                            By:    /s/ Walter B. Jaccard
                                               ---------------------------------
                                            Title: Vice President
                                                   -----------------------------


                                            CHEROKEE LANDING CORPORATION,
                                            a Tennessee corporation


                                            By:    /s/ Walter B. Jaccard
                                               ---------------------------------
                                            Title: Vice President
                                                   -----------------------------


                                            CHIEF CREEK CORPORATION,
                                            a Tennessee corporation


                                            By:    /s/ Walter B. Jaccard
                                               ---------------------------------
                                            Title: Vice President
                                                   -----------------------------


                                            COAST FINANCIAL SERVICES, INC.,
                                            a Delaware corporation


                                            By:    /s/ Walter B. Jaccard
                                               ---------------------------------
                                            Title: Vice President
                                                   -----------------------------


                                            DIXIE RESORT CORPORATION,
                                            a Mississippi corporation


                                            By:    /s/ Walter B. Jaccard
                                               ---------------------------------
                                            Title: Vice President
                                                   -----------------------------


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                                            FOXWOOD CORPORATION,
                                            a South Carolina corporation


                                            By:    /s/ Walter B. Jaccard
                                               ---------------------------------
                                            Title: Vice President
                                                   -----------------------------


                                            GL LAND DEVELOPMENT CORPORATION,
                                            an Oklahoma corporation


                                            By:    /s/ Walter B. Jaccard
                                               ---------------------------------
                                            Title: Vice President
                                                   -----------------------------


                                            LAKE ROYALE CORPORATION,
                                            a North Carolina corporation


                                            By:    /s/ Walter B. Jaccard
                                               ---------------------------------
                                            Title: Vice President
                                                   -----------------------------


                                            LAKE TANSI VILLAGE, INC.,
                                            a Tennessee corporation


                                            By:    /s/ Walter B. Jaccard
                                               ---------------------------------
                                            Title: Vice President
                                                   -----------------------------


                                            LML RESORT CORPORATION,
                                            an Alabama corporation


                                            By:    /s/ Walter B. Jaccard
                                               ---------------------------------
                                            Title: Vice President
                                                   -----------------------------


                                            NATCHEZ TRACE WILDERNESS PRESERVE
                                            CORPORATION, a Tennessee corporation


                                            By:    /s/ Walter B. Jaccard
                                               ---------------------------------
                                            Title: Vice President
                                                   -----------------------------


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                                            QUAIL HOLLOW PLANTATION CORPORATION,
                                            a Tennessee corporation


                                            By:    /s/ Walter B. Jaccard
                                               ---------------------------------
                                            Title: Vice President
                                                   -----------------------------

                                            QUAIL HOLLOW VILLAGE, INC.,
                                            a Pennsylvania corporation


                                            By:    /s/ Walter B. Jaccard
                                               ---------------------------------
                                            Title: Vice President
                                                   -----------------------------


                                            RECREATION LAND CORPORATION,
                                            a Pennsylvania corporation


                                            By:    /s/ Walter B. Jaccard
                                               ---------------------------------
                                            Title: Vice President
                                                   -----------------------------


                                            RECREATION PROPERTIES, INC.,
                                            a Mississippi corporation


                                            By:    /s/ Walter B. Jaccard
                                               ---------------------------------
                                            Title: Vice President
                                                   -----------------------------


                                            RESORT LAND CORPORATION,
                                            an Arkansas corporation


                                            By:    /s/ Walter B. Jaccard
                                               ---------------------------------
                                            Title: Vice President

                                                   -----------------------------

                                            RESORT PARKS INTERNATIONAL, INC.,
                                            f/k/a Shorewood Corporation,
                                            a Georgia corporation


                                            By:    /s/ Walter B. Jaccard
                                               ---------------------------------
                                            Title: Vice President
                                                   -----------------------------



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                                            TANSI RESORT, INC.,
                                            a Tennessee corporation


                                            By:    /s/ Walter B. Jaccard
                                               ---------------------------------
                                            Title: Vice President
                                                   -----------------------------



                                            THE KINSTON CORPORATION,
                                            a South Carolina corporation


                                            By:    /s/ Walter B. Jaccard
                                               ---------------------------------
                                            Title: Vice President
                                                   -----------------------------


                                            THE VILLAS OF HICKORY HILLS, INC.,
                                            a Mississippi corporation


                                            By:    /s/ Walter B. Jaccard
                                               ---------------------------------
                                            Title: Vice President
                                                   -----------------------------

                                            WESTERN FUN CORPORATION,
                                            a Texas corporation


                                            By:    /s/ Walter B. Jaccard
                                               ---------------------------------
                                            Title: Vice President
                                                   -----------------------------


                                            WESTWIND MANOR CORPORATION,
                                            a Texas corporation


                                            By:    /s/ Walter B. Jaccard
                                               ---------------------------------
                                            Title: Vice President
                                                   -----------------------------


                                            WOLF RUN MANOR CORPORATION,
                                            a Pennsylvania corporation

                                            By:    /s/ Walter B. Jaccard
                                               ---------------------------------
                                            Title: Vice President
                                                   -----------------------------


                                            UST WILDERNESS MANAGEMENT
                                            CORPORATION, a Nevada corporation


                                            By:    /s/ Walter B. Jaccard
                                               ---------------------------------
                                            Title: Vice President
                                                   -----------------------------


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