Here are a few Florida parks you might want to research. I've stayed in all of them from a few days to a few months. They are good solid RV parks with plenty of amenities. Prices vary and the further south you go the prices rise.
http://www.crosscreekrv.com/http://www.riversidervresort.com/http://rockcrusherrvpark.com/http://oldemillstreamrvresort.com/http://miamicamp.com/