I asked pretty much the same question, but under "on the road again". Didn't get any replies, so maybe I should've post it here like you, eh?
I can tell you about one place. Big O RV Resort, in Okeechobee. I've visited my folks there...they've stayed there the past 5 years or so. Nice park, great people, lots of activities, etc. They are privately owned lots, but a number of the owners rent them out. I've been lookin at them occasionally, and would hazard a guess that for the winter, the average is about 600-800 a month. They have listings on the BigO website...I think actually BigO sets the price.
They are on the canal, so if you have a boat you can access lake Okeechobee from there which is why I'm looking at it. Spaces are sizable enough, some are even double lots.
I'm personally looking everywhere from there to SC...right now, looking at two months in FL and 2 in SC. I need my fishing...i LOVE my fishing !