I am a Brit who is planning a road trip across the US for next summer. I have got most of my route sorted, and have a pretty good idea of where I am going to stop and what I am going to see. However, I am a bit stuck for ideas between Chicago and Mount Rushmore. Can anyone recommend any sights/attractions on the way? Or any towns that you think I should stop in? It will be myself and my boyfriend, and we are 22.