South Florida Campground

I would second Miami-Everglades campground which is just north of Homestead. It's a short drive through Homestead to the Keys which will give you an opportunity to take your time driving the Keys. Their website is below.

http://www.miamicamp.com/

We have used Jonathan Dickinson as a stop over on the way down. As mentioned above, the new section has large sites and full hookups.
Most often, we stay at Miami-Everglades prior to heading to KW.

Jonathan Dickinson SP would be an option. For something a little different there is Lion Country Safari near WPB. they operate a KOA next door and run special deals that include park entrance all the time making it a decent value. Hearing the roaring lions in the CG is pretty cool. Also you may want to drive on to John Pennekamp state park in Key Largo. The beauty of the Keys doesn't really get good until you get out of Key Largo.

http://www.lioncountrysafari.com/koa/koa-rates/

Just north of that area at Hobe Sound is Jonathan Dickinson State Park just off A1A. Pine Grove campground is newly rebuilt with large sites, close to the entrance.The river campground is further in, more foliage. If you have time, stay an extra night - it is fun to take the river trip on the Loxahatchee back to the "Wild Man's" homestead for a ranger tour. Amazing river scenery and wildlife, another world.

I suggest john prince park. I have not personally stayed there since I live in Boynton,and it is so close.but I hear a lot of good things about it.i plan on it soon though. It is run by palm beach county

Click here for linkhttp://www.pbcgov.com/parks/camping/johnprincepark/

Have you checked out http://www.rvparkreviews.com/regions/Florida/