If your schedule permits a couple days to acclimate will make your trip much more enjoyable. The upper parts of Imogene are the toughest, on the Ouray side you probably don't want to go past Sneffels, and on the Telluride side no higher than Tomboy mine with your Dad on a KLR. If you wanted to attempt it, it's probably easier east to west.
You don't want tall highway gearing for engine braking, and no half worn brake pads.
You can experience most of Black Bear by going from Telluride up to Bridal Veil Falls, you can go as high as the driveway to the old powerplant atop the falls, past there it's one way only coming down.
You guys can ride Ophir, Cinnamon and most of Engineer, I wouldn't go any further west on Engineer than Mineral Point. Between California and Hurricane if you aren't careful you can get sucked into Poughkeepsie pretty easy. Two years in a row one of our group got down by Lake Como by mistake and it's difficult getting back up outta there.
There's a bunch of stuff on both sides of the Animas River valley between Animas Forks and Silverton. It would be a few miles of pavement, but a trip to Creede is worth it. Interesting geology and old mining relics above town.