I've been up Buck Bald two times and both times I took Trail 82 to the gravel road. Never been up on just the gravel road. I was also following so I was paying more attention to the tail lights in front than the way I went. Very pretty view from up there.
Wesser Bald is not accessible by motorized vehicles. The Appalachian Trail runs right by it so it would be a tough one to poach unseen. (not my style) The closest access is to take Otter Creek Road to the top of Tellico Gap where the AT crosses. It is a nice hike up (1.5 miles). Or you could keep riding down Tellico Road. It is actually more fun to ride up Tellico Rd.
+1 on Rainbow Springs Rd, Wayah Bald, Tatham Gap & Needmore Road
You might also try...
FS 308 AKA the Gravel Dragon which runs from Andrews to Snowbird area
FS 81 which is the gravel road that parallels the Cherohala Skyway
Tuni Gap Road / Tuskeegee Road Loop (Big Choga Rd off of Junaluska Rd)
All are gravel roads that are suitable for larger DS and Adv bikes.
One of the best roads is lost to us ... Winding Stairs has been closed for over a year now and looks like it will not reopen.
Sure the gate is easy to ride around but again, that is not my style.
PM me if you want more specifics. I am uncomfortable advertising these roads on the open internet as we are losing access daily and the last thing I want is for masses of hooligans to cause problems.