Elk Horn, IA has a wonderful quilt shop and dutch windmill (small town, but lots of fun stuff). Walnut, IA is an antique paradise and also has a couple of quilt stores.
These are both just a short hop off of 80. Have a safe and fun trip.
Des Moines, IA has many fun things "living history farms" and the Machine Shed Restaurant are right off of 80 and very popular.