If you're into caves and such, I would highly recommend stopping at The Lost Sea if you are going through TN....it should be on your way. It's only just a few miles off of the Sweetwater exit on I-75.....like turn right, drive about 5 minutes and you're there.
Huge underground cave tour, and no you won't get dirty. There's a big ass lake at the bottom of the cave and they take you on a boat ride across it too. Tour takes about 45 min to an hour and well worth the trip. It's like **** you see on horror movies like The Cave where there's all those underground water chambers and such. Definitely something to see at least once in your life, I've been 3 different times with different folks.
http://www.thelostsea.com/aboutus.html