In reply to gfpowell: I went through Grand Junction last time in exactly the conditions you describe. It depends on what car you've hired. The last time we (2 of us) went for the cheapest option, and were told on arrival that they didn't think it was suitable for going as far as Ouray in winter. They said that they would supply snow chains, but we weren't allowed to put them on the car for insurance reasons. They actually said that.
They then tried to flog us a 4WD truck at easily double the cost. We ignored all the dishonest practices they tried (and they tried many) and took the small car and we got there just fine, although we stopped in Glendale Springs for a motel because we were exhausted by that point. The road is obviously extremely good, just beware that it goes high so there might be snow. You just have to drive sensibly if so. We did and had no problems. If you've hired a truck then there's no need to worry about anything.
