We towed our trailer from Chicken to Dawson City in August 2013 and our only problem was two flat tires on our truck due to rock cuts from a construction zone just west of the border. That's probably the section that's now paved. We had no problems on the narrow, no-shouldered, hair-pinned, gravel section of the Taylor "highway." But maybe that's because we are accustomed to towing on narrow gravel, even dirt, roads in the mountains of Colorado. So, as Joe said, it's all in the eyes of the beholder.
If over the road tour buses can make the same journey, a motorhome can--if driven with care at an appropriate speed.