Depending on how much time you have we've stayed at Maria's by the Sea which is very close to the ferry dock and downtown. We've also stayed at Fort Burt, which is across the street (up on the hill and overlooks the marina) from TMM. (A little dated and not as much to do here if you have a lot of time on your hands.) Both were fine for a night and very convenient for where we were chartering from.
We've also stayed at the Sugar Mill for a few days after a charter. Had a great time and it's a wonderful property, but seemed more for extended stay rather than a quick night before a charter.