NYC to Seattle cross country drive–places to stop/things to do?

My husband and I are stationed in Savannah, GA and are PCSing to Ft. Lewis, WA. We are driving from Savannah to northern NJ to see my family then across the Northern part of the US to Seattle. Any suggestions of places to stop and landmarks to see? We dont have any kids, but we will have our dog with us. The places we plan to visit are: Cleveland, Chicago, Milwaukee, Minnesota, Mt. Rushmore.