Have fun! Kentucky should be pretty awesome at that time of year.
The more I feel my age, the more inclined I am to think that there are fewer hills in Cycling Heaven than I used to imagine. ;-)
The campground in Carmi is about 20 or so miles south of the interstate between St. Louis and Louisville where it crosses the Wabash River, so if you are in a hurry either coming and going it could be a convenient and inexpensive stop. If you go there you'll pass through Crossville, where my 2nd great grandfather was the first blacksmith. If not for the one four way stop in town you would likely miss it on your way through.
Harmonie State Park on the Indiana side of the river is huge and is also very nice. And New Harmony, Indiana is worth learning about. There used to be a bridge from Crossville to New Harmony, but it has been closed for several years now and there is no money to replace it.