What does "reasonable expensenses" mean?

There are a lot of factors that affect the answer. There are almost never clear rules about what is "reasonable." You always have to look at the facts on a case-by-case basis. Who is living there now? Are they a beneficiary of the trust? If so, are they a current income beneficiary? Does the trust direct that the property be disposed of? And so on. Still, it appears that the people have been given the equivalent of a life estate (terminable upon departure). That means that they would have to pay all costs associated with living there. However, the answer is complicated by the other terms of the trust and who are the income/principal beneficiaries, etc. Whatever the result, however, I would recommend that you enter into an enforceable lease agreement that explains the terms of the trust and what the resident must do to continue residing there. You will have a heck of a time evicting someone under these facts without a written lease. Given everything at stake here, you really ought to bite the bullet and hire a lawyer. It sounds to me like you are in a situation where you have conflicting duties as trustee and you are only going to be able to fulfill your obligations with the help of an attorney.