Why are the sites posted for sale as expensive as a condo?
Even in a depressed real estate market, there are still a lot of boomers looking for a winter home and willing to pay, what to many, are high prices. You are seeking something in an area where a lot of others have the same idea. Condo prices, due to oversupply and a lot of issues with poor construction, many unsold units turned into rentals, and problems with HOA finances are much more distressed than other real estate. As very small time investors, DW and I would not touch a Florida condo with a ten foot pole.
Many (most?) of the rv lots for sale now may have been bought during the boom times and sellers either are way underwater or still have unreasonable expectations of worth when selling. DW and I have bought a few fire sale rv lots in FL in the last few years and resold them, but IMO, most of the good deals are gone. If you are looking for a bargain investment you may have to go elsewhere. If you want a desirable rv lot in a good location, you may have to pay what I call full retail. Good luck.