From Kansas City, you could simply head west through Missouri on I-70, stopping at Columbia and St. Louis. Missouri has lot of little things to do with historical markers and such. Maybe even heading beyond to Springfield, IL and see the stuff on Abe Lincoln. I-70 is not an especially pleasant road as far as the midwest is concerned, though. One of the advantages of the midwest is the open road with relatively little traffic.

You could also head up north to Nebraska but not to the badlands, just going along I-80, visiting Lincoln (tour the State Capital and visit the Museum of American Speed or the sheldon art museum, maybe tour memorial stadium) onto Aurora (there's a nice little museum of a famous photographer there-bullets through a balloon stuff) to Grand Island (could visit Stuhr Museum-pioneer stuff) and finishing at the somewhat cheesy Kearney arch ala the final scene(s?) of the movie About Schmidt.