We drove that road again last month, not towing, from South Fork to Lake City and back. Reminded me why I would not want to tow over it. North side is expecially steep and winding. Tight turns, narrow road, and steep grade would be hard on an even a newer truck with good tranny, good brakes, and engine and/or exhaust brakes.
Even though the drive is beautiful, and Lake City area is also, I would stay at an RV park on one side or the other and take a day trip to the other side.
They were repaving the highway on the south side with some one lane traffic. Not too much of a holdup but we did have to wait about 15 minutes for the guide car to return. Most of the highway was pretty good but some of the old pavement was a little bumpy.