Thanks for all the recommendations folks! I spent some long hours investigating many resorts and campgrounds. The wife and adult daughter both preferred NOT to go to a big glitzy resort, so I concentrated on state/county parks in the lower half of FL. Finally found what we believe is a good option in Myakka River SP. I made reservations so we are all set.
The wife and I will be leaving MI in mid November and slowly making our way that direction. Sure glad the rest of the season we won't be looking at having to make reservations that lock you into being someplace at a certain time!