Welcome to the Great American Roadtrip Forum.
You will find that there is a selection of scenic roads along your route, starting with some in western MN.
Are you actually using good quality maps in planning this trip? Details like scenic roads are marked on all good maps. As well you will find that most of the historic sites and natural attractions are marked on the maps as well. In fact, good maps, such as those produced by AAA (free to members) and Rand McNally have a wealth of information you will never see on a little screen.
Not only are maps invaluable during the planning process, they are essential when on the road. Do not be tempted to rely solely on your electronics. Many have done so at their peril, some fatal.
Lifey