Originally Posted by jamawani
Late September and early October can be beautiful, but you can also have early snowstorms. They can come as early as Labor Day. You can usually wait a few days and glorious weather returns, but your schedule is awfully tight. Then you get into early fall rains on the Washington/Oregon coasts by late October.
... I would urge you to consider hitting Banff no later than Sept 1.
Sounds like an amazing trip, but I agree with jamawani that the time frame may be tight.
If you are OK about not being a purist, consider doing what some friends of mine did on their cross-continent trip (San Diego - Vancouver - Montreal - New York City): They took "shortcuts." Eager to reach Toronto to visit me, they went as far as they could on their own steam, and then hitchhiked 500 miles or so with their bikes to Toronto. After visiting for three days, they continued by bicycle to New York City. I believe that they also hitchhiked through a section of the Prairies.
Of course, instead of hitchhiking you can take a train, a bus, or rent a car one-way.