There are many, many great driving roads here in Tennessee. You might consider taking hwy 70 from I-40 (exit 239a) and drive thru the backroads until you hit Rockwood, Tennessee. The drive is gorgeous with some nice curves. It's highway 70 and you'll pass Center Hill Lake (Al Gore has a huge houseboat there, not that it matters).
Here is a google map link:
Lebanon, TN to Rockwood, TN - Google Maps