Calisdad, I agree that most trailers should not go up that road. I had to think long and hard about undertaking this trip, including a very detailed conversation with a CHP officer in Bridgeport. I described my rig to her -- a Tacoma with a 6000 lb. rating and a 2500 lb. trailer, which is ten feet from the hitchball to the axle. She told me that I would have no trouble, and she was right.
But I would say that any trailer that is more than 15 feet from ball to axle should not try that road. And unless you have a huge margin of safety (a tow capacity double the trailer's weight), don't do it. We also carry chains for both the truck and the trailer. We have never used them, but I have practiced putting them on and taking them off on my nice dry driveway. (Not as much fun as doing it in the slush, though.)
And to answer your question about the elevation, we do have to acclimate for a day or so. So, for example, we set up camp on a Monday afternoon (at 9000 feet) and did no serious hiking until Tuesday morning, with a trailhead at 9500 and a slow climb up to almost 11,000 feet. (That's why I take so many pictures -- it's a great excuse to stop and catch my breath!)
