Hi,
I'm from Martinique and I hope I can help you. So this is a good idea for these regions are very touristic. Yet, as you may suppose, it is quite expensive here. Not only the real estate market, but also life in general. Of course, you'll have a lot of things to do if you want to buy and invest (for example, to contact a notary for the papers of the building), as anywhere else.
Elodie.