Around Ft Myers, we really like Gulf Waters RV but I believe it's quite difficult to get a space there at that time of year. I believe several parks in the area impose a 1 month minimum and Gulf Waters is actually 2 month minimum for Feb (i.e. Jan-Feb or Feb-March)
I've stayed at San Carlos RV Park near Ft Myers Beach. Its about a 1 mile walk over the causeway to the beach and is on the trolly line. Its small and sites are very close together but the people are very nice. Many are there for the season. Just made a reservation for staying there in Jan for 12 days.
We have stayed at San Carlos a few times. As the above post said, not a bad walk to the beach and shopping. Trolly stops right outside the park if you want to ride. Moose Club is nearby and a bar/restaurant across the channel We had no problem with getting in with our 43ft MH.