Next time I head east, I plan to get to Maine again. You've made me want to get there now - but it'll have to wait a few years.
I have relatives still in Iowa (my mom was raised there). Pretty basic foods - lots of meat - any kind. Corn this year might not be so good - they are still having a drought, unfortunately. The Amana Colonies (already mentioned) is pretty much German cuisine - lots of meat and potatoes. Like already asked, what part of IA will you be in? Northeastern IA has lots of Norwegians - can find different food there.