I worked at Lambert (STL) and Spirit (SUS) airports. Both will accept G.A. aircraft, for a fee. I always go to St. Charles County (SET) when I fly up for a visit. It is a nice airport with the cheapest fuel in the area. It has no ramp fees. It is a bit out of the way, though. St. Charles (3SQ) it in very bad shape. The runway is VERY rough. It is closer to town than (SET), but is still a little remote.
My recommendation is (SET) if you can arrange transportation. Otherwise, I would go to (SUS), (STL), or (1H0). I can't say anything good or bad about (1H0) because I have never landed there