And WV, could you be pursuaded to shuttle a car/bike/person for money? On trips like this finding a shuttle AND a safe place to leave the vehicle is often harder than the event itself, at least so I've found doing section hikes on the AT for 36+ years.
I parked @ Cass along with other cars and no problems experienced or reported to me by others. The parking places are so far out of the way of the usual partyandsmashupyournewcarwithbeerbottles that it does not worry me. The ranger I met said there were very, very few problems or incidents on the trail. I think most of the parking lots are near enough to houses, not like the A.T. in the middle of nowhere or like the Jersey Shore where the numerous drunken kids in a party shack beat up your car.
The shuttle is a good idea if you don't want to bike uphill. The brochures say the trail is only 1% OVERALL, but I know its more than that in the south and middle sections.
The Greenbrier Rail Trail was worth the 6-1/2 drive down there.