Pete - I have read your journal before, so compared it to my log from last summer - it's eerily similar. Something like 80%of the stopping points are the same, and my days from Eugene to Pueblo is within 1 of yours. So I see your point on 7-8 weeks being long. My only thoughts being 1) I was worn out when I got to Pueblo; 2) I'll be starting out in not as road hardened shape this year. I am training with load, but it's not the same, and 3) I am solo, so no help with wind. Maybe I should thus figure 5-6 weeks. That suggests no fall color, but similarly (I think) NO fear of cold.
Another interesting observation - You had record heat through Montana, wearing at your Easterner Cold weather experiences. I on the other hand had record (ok, near record) cold and wet with Lolo pass being impassable by bikes due to snow the day after I crossed, wearing at my desert rat weather experiences.
So If I now figure ending mid September instead of late September I wonder if I can largely dispense with cold weather gear entirely?? That would really help. No fleece jacket, no down vest, maybe even switch to a summer only sleeping bag??? A thought.