What is there to see on my trip home?

I'm traveling home from Boston, MA to Boise, ID. I figure I'll take either 90, 80, 70, or some combination of the three to make most of the trip home. Can I have some good suggestions on what detours I can make along the way that will enrich the drive? I'm willing to add a couple days or ~150 miles/destination. Any serioius suggestions will be considered and I'd like to make a Yahoo planner map when all the suggestions for my trip are added in.|||Hannibal, Mo. Yellowstone. Field of Dreams in Iowa.