If you go through Kansas City, get some BBQ. It is after all the BBQ capital of the World. Check out Oklahoma Joe's. Awsome ribs.
http://kansascity.about.com/od/resta...BQTopPicks.htm
Part of the fun of a trip like this is just discovering things along the way. I'm sure in the south there are plenty of interesting places along the way. Civil war battle fields. Old plantations. Graceland! Depends on what your into.
Personally, if your a sports fan, I would try to catch some ball games along the way. Also Deadwood in South Dakota. After watching the series my interest has been peaked.