Two destinations I have really enjoyed chartering are Belize and the Grenadines. In Belize you can start either in the north end of the island chain, Ambergris Caye, or the south end, Placencia. We have done both and some of my party liked the south while I liked the north. Either way it is much more isolated than most other destinations - pick an island, the drop anchor and be all by yourself.

Some approach the Grenadines from St. Lucia and Granada but we have always chartered in St. Vincent. A bit more robust sailing than BVI but wonderful islands.

Good luck.