I'm living in Iowa, just a stones throw off Interstate 80 which is the hwy I'm guessing you will be taking as it's the main hwy that runs through the state. I have 4 shops for you that run along that hwy...
#1 The Little Red Hen in Muscatine, Iowa (my favorite)
#2 The Fabric Stasher Quilt Store in Tipton, Iowa
#3 Cotton Creek Mill in West Branch, Iowa (a few miles from #2)
#4 Inspired to Sew in Cedar Rapids, Iowa
#5 Sky Blue Quilt Shop in LeClare, Iowa....this is one I have not been to yet, but I hear good stuff about it.
If you are taking another route that opens up a whole new can of worms!!