All three hikes will require a shuttle.
For the hike through the GSMNP if you are going NOBO I would park at Standing Bear Farm Hostel (~$2 day) and have them shuttle you to Fontana Dam. If you wanted to do it SOBO, you can park at the Fontana Dam Visitors Center and have the Hike Inn (near Fontana) shuttle you to Davenport Gap.
Standing Bear Farm
c/o Curtis and Maria Owen
4255 Green Corner Rd.
Hartford, TN 37753
Tel. – 423-487-0014
The Hike Inn
c/o Jeff and Nancy Hoch
3204 Fontana Road
Fontana Dam, NC 28733
Tel. – 828-479-3677
For the Roan Highlands hike, I recommend parking at Kincora Hostel and have them shuttle you to Erwin and hike north, but if you wanted to go south you could park at Uncle Johnny’s Hostel in Erwin (~$2 day) and have them shuttle you to Dennis Cove.
Kincora Hiker Hostel
c/o Bob Peoples
1278 Dennis Cove Rd
Hampton, TN 37658
Tel. – 423-725-3039 alt 423-725-4409
Uncle Johnny’s Nolichucky Hostel
151 River Road
Erwin, Tennessee 37650
Tel. – 423-735-0548
For the Virginia Highlands hike, you can park in Damascus at the public parking lot near the old mill (across from the post office) and have Mt. Rogers Outfitters shuttle you to where the trail crosses near Marion. There is also a shuttle driver that I have used that has the username “Lonewolf” on http://www.whiteblaze.net that I have used in the past and been very pleased. I don’t know of a shuttle service in Marion if you wanted to go SOBO instead, but there probably is one somewhere.
Mt. Rogers Outfitters
110 W Laurel Ave
Damascus, VA 24236
Tel. – 276-475-5416
I have used all of the above shuttle services in the past multiple times with the exception of Mt. Rogers Outfitters, whom I have never used but heard good things about.