For you PA and north east guys, if your going to Nashville, it's probably better to go the I-81 to I-40 route down through Bristol and Knoxville. I've made the trip that way and to me it's not nearly as brutal as going across the mountains through WV and PA. If you really hate yourself, take 70 to 68 through WV over to 79 south through to 64 out toward Huntington. That would be quite a workout towing. 81 is pretty flat until you turn across the mountains down toward Bristol. Once you get past Kingsport, if memory serves its pretty smooth sailing the rest of the way to Nashville. For you west coast guys especially in SoCal. Get on I-40. Drive. A lot.
Over in KY, I've pounded that stretch of 64 over from the Huntington to Lexington a lot. It's not too bad the further you get from WV the better. The bluegrass parkway out of Lexington is also not too bad save a few hills if memory serves down toward Elizabethtown where you meet up with I-65. If truck traffic bothers you, 65 is not the place for you. It's the major north-south artery in that part of the country. I watched my dad white knuckle that stretch a couple times. Doesn't bother me. It does him though.
Anyway... watching..... waiting...