Take a 2 week trip down here and stay in the following areas: Corozal, Orange Walk (probably Lamanai is the best place to stay in that area or Gallon Jug), San Pedro, Caye Caulker, Cayo, Hopkins, Placencia and Punta Gorda. Book your first one or two places for dates and then do the rest of your tour by the seat of your pants (know where you are going to stay though). Talk to the people at the hotels and hang out at expat bars.
That will give you a good idea of where might want to hang your hat. After that's done make a second longer trip and see if it's really what you want to do.