<PAGE>   1
                                                               Exhibit No. 10.41

                   SUPPLEMENT NO. 3 TO GRANTOR TRUST AGREEMENT


         THIS SUPPLEMENT NO. 3 TO GRANTOR TRUST AGREEMENT (this "Supplement") is
made and entered into as of the 18th day of May, 1999, by THOUSAND TRAILS, INC.,
a Delaware corporation (the "Company"), and a majority of the persons presently
named as beneficiaries under the Grantor Trust Agreement, dated as of May 8,
1991, as supplemented (the "Trust Agreement"), between the Company and UNION
BANK OF CALIFORNIA, N. A., as Trustee (the "Trustee").

RECITALS

         A. The Company, as the successor to USTrails Inc., a Nevada corporation
formerly known as NACO Finance Corporation, entered into the Trust Agreement to
provide, among other things, for the funding of its indemnification obligations
to its directors and officers under indemnification agreements, its constituent
instruments, and applicable law.

         B. Pursuant to Section 12 of the Trust Agreement, the Company and a
majority of the persons presently named as beneficiaries under the Trust
Agreement desire to provide for the termination of the trust created by the
Trust Agreement (the "Trust") and for the distribution to the Company of all of
the assets in the Trust as of June 30, 1999.

         C. There is no litigation or other proceeding pending or threatened
with respect to any Claim (as defined in the Trust Agreement) and no beneficiary
under the Trust Agreement has given notice that any Claim is likely to be
asserted in the future on the grounds of evidence known to or suspected by such
beneficiary.

AGREEMENTS

         NOW, THEREFORE, the Company and a majority of the persons presently
named as beneficiaries under the Trust Agreement, intending to be legally bound,
hereby agrees as follows:

         1. Pursuant to Section 12 of the Trust Agreement, the Company and the
ten (10) persons signing below, who represent a majority of the nineteen (19)
persons presently named as beneficiaries under the Trust Agreement, hereby agree
and consent to the termination of the Trust as of June 30, 1999, and to the
distribution to the Company of all of the assets in the Trust as of June 30,
1999. For this purpose, the Trustee is authorized and directed to (a) determine
the market value of the assets in the Trust as of June 30, 1999, and (b)
liquidate and distribute to the Company an amount equal to one hundred percent
(100%) of the market value of the assets in the Trust as of June 30, 1999.

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<PAGE>   2

         IN WITNESS WHEREOF, this Supplement has been executed and delivered as
of the date first above written.

                                                THOUSAND TRAILS, INC.



                                                By:  /s/ William J. Shaw
                                                    ---------------------------
                                                    William J. Shaw
                                                    President and Chief
                                                    Executive Officer













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<PAGE>   3



                     AGREEMENT AND CONSENT OF BENEFICIARIES

        The undersigned, a beneficiary of the Trust Agreement referred to in the
Supplement No. 3 to Grantor Trust Agreement attached hereto (the "Supplement"),
hereby acknowledges receipt of, and consents and agrees to, the terms of the
Supplement.

<TABLE>

<S>       <C>                                 <C>
Dated:     May 18, 1999                        /s/ Andrew M. Boas
           ------------                        --------------------------------
                                               Andrew M. Boas

Dated:     May 18, 1999                        /s/ R. Gerald Gelinas
           ------------                        --------------------------------
                                               R. Gerald Gelinas

Dated:     May 18, 1999                        /s/ Kenneth E. Hendrycy
           ------------                        --------------------------------
                                               Kenneth E. Hendrycy

Dated:     May 18, 1999                        /s/ Walter B. Jaccard
           ------------                        --------------------------------
                                               Walter B. Jaccard

Dated:     May 18, 1999                        /s/ William P. Kovacs
           ------------                        --------------------------------
                                               William P. Kovacs

Dated:     May 18, 1999                        /s/ Donald R. Leopold
           ------------                        --------------------------------
                                               Donald R. Leopold

Dated:     May 18, 1999                        /s/ H. Sean Mathis
           ------------                        --------------------------------
                                               H. Sean Mathis

Dated:     May 18, 1999                        /s/ David A. McCrum
           ------------                        --------------------------------
                                               David A. McCrum

Dated:     May 18, 1999                        /s/ Douglas K. Nelson
           ------------                        --------------------------------
                                               Douglas K. Nelson

Dated:     May 18, 1999                        /s/ William J. Shaw
           ------------                        --------------------------------
                                               William J. Shaw
</TABLE>


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