I have a Jayco 28bhsw TT and a 2500HD. Traveling with wife and kids, 2 and 5(they're troopers, trust me). I'm hitting a friend's place(private campground) near 76 falls in Lake Cumberland heading sout...
We did the full Skyline Drive and Blueridge Parkway a few years ago in our 32' Class C which was a little over 11' tall. We drove every inch of it, only getting off for gasoline, and getting back on at the same spot. There were some places where it was tight, but nothing un-doable. At several of the tunnels, we waited until there was no oncoming traffic and drove in the center of the road.