I would recommend you fly into Edmonton and ride over to Jasper then down to Banff to connect with the Great Divide. The big drawback is it will be cool with possible snow. Very very scenic however.
Once you are near the southern end of the GD, I would suggest you break off at Silver City (cool town) and ride to Lordsburg (get a train if you are running behind), then to Animas. From there you can either ride south on NM-338 to CR-3004 (Geronimo Trail) to Douglas, AZ (at the US/Mexico border) OR you can ride another scenic road west to Portal, AZ; gravel to Chiricahua NP with a ton of hoo doos (eroded stone pillars); to Douglas (another neat town). If you want to end up in Antelope Wells, you can take Mexico 2 from Antelope Wells to Douglas.
From Douglas, you can continue west on NM-92 to Montezuma Canyon Rd (very remote gravel) to Parker Canyon Lake to Sonoita via AZ-83 to Green Valley to Tucson. If you are tired of gravel, take AZ-92 to Sierra Vista then over to Sonoita thru the Fort Huachuca and AZ-83.
Tucson is a good finish as it has planes or trains. Amtrak, the US train service, has HUGE bike boxes.
For a detour, you might consider breaking off in Jackson, WY and heading south to Alpine, WY then take Greys River Rd./Emigrant/CR-306 to Kemmerer, WY. From there head over to Manila, UT then toward Maybell, CO via Browns Park Rd./CO-318. Between UT border and Maybell, head north on CR-10N to CR-25 just over WY border. Head east on extremely remote CR-25/CR-4 (not scenic, to me at least) to Baggs, WY, then WY-70 to CR-129 where you reconnect with GD. The roads between Alpine and Kemmerer are very beautiful and very quiet. You miss a lot of the heat of the Great Basin but CR-25/CR-4 are just as wide open as the Great Basin (check streetview on Google maps). Again, this alternate is very remote for long stretches.
If you want GPS routes or cue sheets, contact me privately and I will send to you in December.
Best wishes on your trip!