This brings back many memories. As a kid in college 50 years ago I got a wild idea and free climbed the face of Amicalola Falls with a buddy of mine. Man was I nuts! I hope I have become smarter with age!
Both parks are quite beautiful-- and getting to the mountain tops is rewarding. But getting up to either of them is more than I can chew on with anything but the very lightest weight and shortest of RV (trailer or motorized). While I would do them now only in my truck camper but never with my current 5th wheel, and I would never do them back when we had our class A and Class C. Not only is grade an issue but the switchbacks are 180 degree tight switchbacks (Not many switchbacks on Amicalola).
Going down is as bad if not worse than going up.
I think I'd add Brasstown Bald to my list of roads to avoid with an RV in GA also. Back in the early 1980s I tried that one in a Class C and smoked my transmission. Only made it half way up, and was running out of RPM's in 1st. Tranny got red hot and smokey. Managed to turn around and limp back to the base of the mountain. Learned my lesson on that one.
