If you know what area your looking at relocating to, research the campgrounds in the area for information on rates and look closely at them and any reviews you can find. Remember you are not just looking at buying the RV and truck, you also have to have somewhere to park it, and then you add utilities.
There are a lot of really nice rv parks in Florida, but a lot of the ones where people live long term are restrictive in different ways, some only accept folks above a certain age. Some place age restrictions on the RV, and the ones that have no restrictions can become run down quickly.
If you don't already have a park in mind, I'd research that before jumping in with a camper.
If you are still of a mind to continue, go to an RV show or a dealer, start by asking about units around 30' For something to be comfortable in full time you will likely want to be in that range, maybe a little more.
For Florida, you will want a well insulated unit with at least a 15k btuh AC unit. and preferably a second AC.
There are quite a few folks in here from Florida, mentioning what area and what amenities in the park you want may net you a lot of local knowledge.