Back of the Dragon, obviously. I'm headed that way today, in fact. Check out Burke's Garden (God's Thumbprint) nearby, while you're at it.
@warp9.9 recommended that one to me long ago.
Continuing on Hwy 16 north of Tazwell is "The Tail of Dragons" going all the way up near Parkersburg. I may do that tomorrow and will let you know if it's worthwhile.
The Snake, Devil's Triangle you mentioned. I'd add Aces and Eights (some of that route may still be closed) and Copperhead Road. That's
@Dr.D and
@rainman territory, so they may chime in with more suggestions from that area.
Sounds like a good time- enjoy!