The one place in Iowa that I would suggest you make sure you get to is Coffee Cup Cafe in Sully. My cousin said it was both the best pancakes and pie he has ever had. And I would never dream of going to Omaha without at least one meal at The Bohemian Cafe.
I think you will really like the guberburger at Wheel Inn. I’m glad you are going to make it there before they close. It sounds like a great trip!