I am interested in doing some camping in Southeast Missouri also. Years ago we camped at most of the ones already listed, so I wanted to find something different. I just did a google search and found a lot of campgrounds that I didn't know were there.
Google----- campgrounds in southeast Missouri .
Most of them have reviews listed.
We just camped at Cuivre River State Park this past weekend. That campground is North up by Troy, Missouri, but is a nice campground. That was our first time out with this camper since buying it last Jan.
Good Luck and happy camping!