Your best bet for a Florida state park reservation is as follows:
You need to go on Reserve America at exactly 8:00 AM eastern standard time eleven months prior to your starting date.
A day or two ahead of time you can see what sites will be open.
On your computer have a split screen. One of the screens should be the US official time, (so you can watch the count down.
On the other screen you need all your ducks in order and have the site that you want all picked out. At 7:59: 59 click the button and say a prayer.
My wife used to have six or seven browsers open and and click them as fast as she could. Normally she would gt a site.
We also had a group of friends who worked together with each of us having the others info and credit card numbers.
This may sound like nonsense, but believe it or not we would be able to snow bird the entire winter using this method (two weeks at a time per state park)
Thankfully a few years ago, we bought a lot in a RV park in Key Largo and ever since have been happy campers and able to sleep late on those 8:00 am days.
Guy