Generally speaking I think that most people can make it to, or just beyond 6400', which is just before the 1st switchback and directly below the road as it comes out of the 2nd switchback and resumes its westerly coarse heading into the canyon. We got a jeep to 7700' on the road before we had to stop due to large rocks which had fallen on the road. If we had to start before the switchbacks we would have hiked directly upslope rather than hike the road. In that case we would have added around 1300' and 1.5 miles. Given the nature of the climb its not too much more to add, and its all relatively low elevation so it should not be very difficult.
We found in December that snow tended to collect on the upper or second switchback since it is in the shade for most of the day and it is an area where snow tends to fall onto and sit. It is good to park low to avoid a freakish storm, but I also think its good to park before the switchbacks if you can't make it all the way past them, since you actually add more mileage to the climb by hiking them.
Last edited by jhodlof; 02/23/09 11:51 PM.