I recently sold an Island Packet for a client here in Florida. (I am a boat broker.) I got to know them fairly well. Nice folks. They spent 7 years cruising and decided it was time for a change. Over cocktails I asked them to tell me a bit about their trip. Short story--they spent four years in the Bahamas and three in the Caribbean. They said that if they had to do it over again, they would have spent all seven in the Bahamas. There was so much to do and see and they enjoyed the Bahamas and the Bahamians more than anywhere in the Caribbean and after four years they felt they had only begun to get familiar with them. After spending a month there myself this past spring I can tell you that my month off was not anywhere near enough time. But this work thing keeps getting in the way of my sailing thing.
Buy a boat in Florida where the supply is good, the prices are still attractive, and there is a tremendous amount of local talent and equipment available at good prices so you can prepare your boat for the big cruise. Watch the weather and head south for the hurricane season and you can always lay up in Trinidad which has good services and storage.