Carribean/Central American Country Suggestions?

Hi!

hope I'm not repeating something by asking this, but wondering if anyone has suggestions for a good destination in this area for a young(at heart!) 30-something woman to go as a solo traveller in January? I am hoping to avoid any place where the polished package holiday resorts dominate the skyline, but somewhere with a chance to meet some similar low key travelling types/welcoming locals would be ideal....Many Thanks for any suggestions!