Chicago is 12 hours by Amtrak train from Newton (~25 miles north of Wichita). Last minute roundtrip coach fare is $152.00. One train in each direction, and it's quite a bit faster than Greyhound. Ugly early morning train times in Newton, though.

Failing that, looks like advance purchase airline tickets are running around $242 roundtrip. That doesn't seem too terrible, actually. AirTran is helping to keep fares down.