There are many people who contribute here everyone has their own way of addressing issues. Your question has been asked so many times and could get an answer by searching previous threads. The availability of rental houses in Caye Caulker has been discussed many times. There are not a lot available, especially during the tourist season. There are more in San Pedro. You don't indicate what you require in number of bedrooms, whether cable is important, etc. What is the price range you are looking to spend? If you ask specific questions you have a better chance of getting answers you might be able to use.