Michael McCoy, who laid out the route, has updated his book, "Cycling The Great Divide". The guide now includes Canada, and various route changes, such as a new segment avoiding the interstate into Butte. It is a great resource for anyone planning on riding the route. Available here:
http://www.amazon.com/Cycling-Great-Divide-Michael-McCoy/dp/1594858195/ref=sr_1_1?ie=UTF8&qid=1384354367&sr=8-1&keywords=cycling+great+divide