I just looked up your routes, since I'm sitting in the airport waiting for a flight home from a cycling trip to Colorado. I rode your first day's route, the Copper Triangle, and was planning on riding the 2nd day (Ute Pass) but bagged it in favor of riding in the Denver foothills with friends.

My comment is to not underestimate these rides, especially doing them on back to back days. The altitude affects different people differently, but figure these rides will be 20% harder on account of altitude. Copper Triangle heads over 3 mountain passes, two of which are an elevation of over 11k feet. The Ute pass ride is a little easier but still not easy.

I don't think too much of riding 100 miles with 8000 ft of climbing in a day, but I found Copper Triangle to be a pretty tough ride, especially climbing Vail pass at the end.

If you can arrive a few days in advance and spend some time in Denver, that will help you acclimatize to the altitude.

Since you only have 3 weeks until the event, I'd ride a lot and work out the logistics of the bike. Make sure you feel comfortable with it. Also be aware that there are some long descents and also riding down the Vail Pass on a narrow bike path with lots of people on it.

Beautiful epic riding, though!!!