Here's what we did. Disclaimer: This was over the 2015-2016 winter which was before the big push in buying RVs, but I believe that 90% of the big push was bought by working people who won't be spending the winters on the Gulf Coast.
We left New England Nov. 1st and got back on May 4th. We stayed at most places 1 week, usually traveling on Wednesday. We knew where we were staying next and I was looking for a place to stay the stop after that. We had advanced reservations only at places we wanted to be at a certain time.
We never had a problem getting into a place, and I don't even think I had to call more than a couple of campgrounds in one area. We alternated between private and public CGs. We started down the east coast (Myrtle and Hilton Head) then the W. Palm area in FL, over to the Sarasota area then out the panhandle and around the gulf coast to Galveston. We worked our way back through OK, Arkansas, the Ozarks, KC and east from there.
I believe the reason this worked is because I was picking up cancelled plans. The roughly 2 week out period, plus not checking in on a Friday seemed to work for us.
We wanted to get further south in Florida - like down towards Naples - and there were sites available at private CGs, but the price was above what we decided was reasonable (> $100 a night).
Jerry & Jeanne
1996 Safari Sahara 3530 - 'White Tiger'
CAT 3126/Allison 6 speed/Magnum Chassis
2014 Equinox AWD / Blue Ox