Well, being in KC, Kansas Rocks is closer, but I used to work weekends, so I ended up going to Tuttle Creek most of the time. There is also S.M.O.R.R., near Seymore, Mo. Here are a couple of web sites I found, not sure how accurate they are, RiderPlanet USA - ATV Trails, Motorcycle Trails, Motocross Tracks
. The first one, Rider Planet, is mostly for ATVs and bikes, but they do have some 4x4 places listed. You might want to check into a local club, some of them have access to private property.