Our daughters live north and south of us; one in Chicago and the other in St Louis. We can take Old Route 66 either direction instead of I-55. It's so nice! There is minimum traffic, and no semi's to deal with as a rule. You can pull off and stop at the DQ if you want and grab a cone or a hamburger...without an exit! You may go through the window cleaner faster in the summer months, but it's worth it. Then during the warmer months, you can stop at Litchfield or Springfield and watch a drive-in movie. Can't do that on 55!
We're going to travel on some other older roads. Old Route 36, right around the Illinois/Indiana border is another scenic area.