Originally Posted by kklems

Branson, Mo 3 hours
Topeka, KS 1 hour (historical sites like the NPS Brown vs BoE)
Wichita, KS 3 hours (west of town 30 miles or so is a salt mine tour and museum (650 feet underground)
Omaha, NE 3 hours
Lincoln, NE 3 hours.
Nebraska City, NE 2 hours (Arbor day lodge and museum)
Des Moines, IA (Ia state capital) 3 hours
Chicago is about 8 hours so not good for day trip but maybe a long weekend

Maybe more south than midwest but
Oklahoma City just under 5 hours(Oklahoma Memorial)
Fayetteville and Benton, AK 3.5 hours.
Little Rock, AK 6 hours

Towns along the Missouri River like Rulo and Brownsville have trails you can walk along side the river and local touristy shops. (2 hours)