Ledges State Park
Ledges is an amazing place. It has so much to do. There are long trails to hike, creeks to play in.
You can bring your tent or RV and camp. The RV camps have water/sewer hookups. The primitive tent sites are usually pretty clean and can get pretty busy on the weekends.
There are lots of bridges that get flooded out and are fun to drive over. Most of the kids like to hang out near them and get splashed.
Its a fantastic place to enjoy the outdoors and especially in the fall. Also if you go to Ames stop at Great Plains pizza company.