In reply to gfpowell:
I drove from Denver airport to Ouray in mid January this year. We went along the I-70 to Grand Junction and then South to Ouray. A lot of the I-70 is dual carriageway but the rest is all single carriageway. The journey there was quite hard work. We had a Kia Sorento that had no fog lights and the headlights seemed pretty useless as well. The whole journey was in darkness and it snowed or was foggy most of the way. I think it took us about 8 hours. The roads were well ploughed and gritted though, it was the visibility that was the problem, nothing that I haven't experienced in the UK however. I can't imagine the roads to Ouray getting so bad that you wouldn't be able to get through being a common occurrence, the ploughing and gritting seemed too good, not to say it never happens. We never had to use snow chains (not sure if we had them?) or 4WD on the whole trip and the drive back was all dry and miles easier.
My only suggestions would be don't get a Kia Sorento and take a few extra long slings or equivalent to extend your anchors when in the Ice park as I found a lot of the time the trees were quite far back from the edge. I ended up buying 15m of static cord because my slings weren't long enough when put together (for top roping or for leaving in place when you're leading, which you're supposed to do there).
It should be great, it's probably the best trip I've been on
