I love Cherrystone. We go every September. Tons for the kids to do: crabbing and fishing from the pier (or rent a boat), jumping pillows, great pool area for the kids, mini golf and always events and activities (the last few years they have had karaoke and a DJ when we were there). Gorgeous scenery! Only negative here is that some of the facilities (bath houses and such) are hurting and need updating.
Large, flat and level spots were great. The pool here is amazing and it’s a designated star watching area and they even “rent“ (no charge!) telescopes from the very nice Visitor‘s Center!
The campground is enormous, so bring your bike! You can choose a spot on the marsh and over the water and there’s you will see your neighbors, but we choose to stay tucked into the back where there are full hookups. There, each site is surrounded by tall reeds and you have near total privacy. The spots are enormous. A quick drive to the other end of the park and there is a beach area for swimming (go early: it gets full in peak season with day use partiers, but it’s still wonderful) and a Civil War fort. Inside the campground is a great nature center which rents kayaks and canoes, and offers programs for the kids.
A nice private catch and release pond, an old little mini golf setup, a small (but adequate) swimming pool kept the kids busy. About 45-50 minutes West of downtown STL, it was close enough to do “city things,” but far enough out that it felt like camping. The real gem is the little town of Washington about 15 mins away which has great restaurants and an awesome ice cream place. We also found a place nearby that rented tubes and kayaks for floating down the Meremec River. The spots are I think a little close together, but, while the facilities are older, they are pretty well-kept.