Highlands Hammock State Park, Sebring, FL is a great place to camp! Kids love it.
River Ranch Resort is also great just east of Lake Wales on 60. The kids in our camping group ranked this better than Ft. Wilderness for them. The rodeo is fun. There is also clay shooting, golf (not so great 9 hole golf course), fishing, horseback riding, airboat rides, swamp buggy tours, saloon with family hours and more. Lots of places to ride bikes etc. The resort has a rental program for sites to rent. Don't confuse it with the River Ranch hunting camps.
We also like CB Smith park in Ft. Lauderdale. It has a large waterpark for kids. It may sound strange going to Ft. Lauderdale to camp, but this is a great park.