From Bozeman, MT to Richmond, VA, you can drive and stop whenever you see a place. Everybody's interests are different.

Maybe Mount Rushmore. Lewis and Clark explored from St. Louis-Sioux Falls, IA-Livingstone, MT-Oregon and there are many historical markers. Each marker may take 1 minute to read. Some are by the highway. Consider stopping if you see one. You might stop by Chicago. Google some cities along the way and see if anything interests you. Maybe museums?