Drive through the waters!
This was my favorite place to go camping as a kid because you could drive through the water! There's a creek/river that runs through the park and the road runs through it in two spots. There are bridges for pedestrians. But for a 7 yr old Midwestern kid this was exciting stuff. This place is great though the campground never fills up so you can still just drive out on a weekend. Nice trails well kept. Also they have a cute lodge and restaurant so check those out too.