Welcome to GS!
I do a lot of work up there: Quad Cities (Bettendorf), Iowa City, Des Moines, and Sioux City. Always rollin' through at some point
Ethanol is a sticky widget. You'll probably gain some FE numbers with regular gasoline, but people use it for different reasons. It depends on your goal. I drove up from KC to Sioux City with a Flex Fuel Monte recently -- had to fuel up in MO, actually -- couldn't find an E-85 station on I-29! Big drop in FE, but the rental probably never saw the stuff before.
Best FE to ya with the wagon. I admire the choice over an SUV