I'm headed to Yellowstone in 3 weeks from Southern Michigan. Towing a 5th wheel. I'm thinking of taking I-80 to Omaha then north to I-90 (Mt. Rushmore). I don't want to take I90 through Chicago. Looking for info on roads conditions(i.e. rough roads). Trying to find smoothest route to Mt. Rushmore. Any info would be great. Thanks