Looks like it's Shawnee National Forest, screw the Mounds, they're certainly significant, World Heritage Site and all, but got a "meh" feeling when researching, especially having been to cool Mayan ruins. Shawnee looks to have all sorts of cool hiking and climbing around. I don't suppose anyone has spent any time around there, in terms of knowing about other attractions, good eats, etc.? Don't make shyt up, dyckheads.
There's a giant Brooks catsup bottle over by Cahokia, but we're just going to have to miss that.