If you're coming from the east on 40, you'll go across the mountain on the NC side of the NC/TN line. It's not terrible, just some curves and grade. If there's construction, it can be a little narrow in places, but stay in the right lane, and you should be just fine. Once you cross over to TN, things are much more "normal" interstate towing. To get into PF from 40, the roads are good with no issues towing (just traffic). Have a fun time!