If the trailer is in your mother-in-law's name, you have no responsibility for the trailer itself: you are not the owners.If the lease for the space, etc. in the community is in your mother-in-law's name, you are not responsible for it, either: you do not inherit another person's leases, contracts, debts, or obligations.If you have a written lease in your name(s), you are responsible under the terms of the lease and would owe the rent, etc. for the full remaining written duration of the lease.If there is no written lease for the community, just an oral agreement or understanding under which you have been paying, you are month-to-month tenants of the community, which means you just owe one month's notice: for example, in this case, if you gave notice today, you'd still owe for February rent, but not after that.