Hope you like your 22 as much as we do.
Missouri state parks take online reservations--would definitely recommend. Also try to select a location that has a town with a Walmart close by in case you forget anything or lose anything.
We have found that in summer, ironically, campgrounds with few trees are actually overall cooler at night than the treed ones, which can trap in the heat and bugs. The more open the campground, the better the breeze and fewer mosquitos.
Plan a mid-day break inside in the AC for a ballgame or movie. You will find that the freezer in the 22 is the correct size for Ben and Jerry's.