Assuming you are heading up I-65 from Louisville to Chicago, I'd suggest a stop at Fair Oaks Farms in northern Indiana.
Their farmhouse restaurant is pretty good, as are the ice cream/milkshakes they make from their dairy herd. They also have tours of their farming activities.
I flew out of New Orleans a few years ago to an event in St. Louis. Of course St. Louis is close to several states and we rented a car while there to drive around to sight see. We saw. Lots of corn. I'm from Mississippi and we grow corn too but not nearly as much as we saw up there. It was just before harvest time which meant that the well fertilized corn blocked your view of anything you wanted to see. We went to a nice gun show somewhere in Southern Illinois but they would not let us even touch a gun unless we had some kind of Illinois firearms card. I saw some nice S&W's but couldn't even touch them, much less buy one and have it shipped home to my FFL. Reading Mark Twain made me want to see what I figured to be a very beautiful Cairo,Ill. I was thoroughly depressed after what I saw there, and a few other places. We did find a nice gun store in Paducah, Ky. And bought a few things there we had shipped to my FFL. The main thing I remember about that trip was lots of corn.
Not sure if you have this kind of time, but swing northeast out of Louisville to Cincinnati, say hi to Rusty, then continue on to Dayton and go through the Wright Patterson Air force Museum (It's FREE!), have a Marinon's Pizza, then jump on I-70 back to Indy, and then north to Chicago.