roadtrip to St. Louis last November. Rather than go directly home, I crossed the Mississippi at Alton, and then headed up Illinois Highway 100, which crosses into that general area as it heads north. Some of the stretches of Hwy. 100 are quite scenic. Unfortunately, the weather sucked that day, so I didn't stop to take pictures.
On the other hand, during the trip to St. Louis, I stopped at a classic Route 66 icon, the Ariston Cafe in Litchfield - in business since 1929, and at its present location since 1935. It's well worth a stop if you're in the area - not just for the history, but for the food as well.