I assume you know about US311 from WV line into Salem Va. It is excellent. How about 250 from staution to Monterey WV. Route 33 from Harrisonburg, Va to Marlinton, WV. In Va route 8 from Flyod to Staurt is great. Route 58 from Staurt back to Hillsville and then 100 back to Pairsburg Va is a good ride. In extreme western Va route 58 and 16 east of Damascus is great.
I used to live in Dublin, Va and went to school in Morgantown,WV with lots of family in SW PA. So I have been riding these rodes for nearly 20 years. There are lots more good roads along the WV-Va line I can name for you. Goshen Pass road from Lexington,VA into WV is a great ride as well.
PS I currently live within 30 miles of the Va line so ride in Va alot.