Generally, what's the latest you could start the Colorado Trail and make it all the way through without being stopped by deep snow? I've heard it can snow on the higher portions in September, but is it really impassible, or just early season snow that you can plow through? I actually like a little snow and I don't mind cold wheather as long as it doesn't get below zero. And I love the fall season. Assuming an average pace, what's generally the cutoff date for starting in Denver and heading to Durango?