The most beautiful fall color I have seen in my lifetime of living in Colorado was last year on Cumbres Pass on the Colorado-New Mexico state line during the first weekend in October. That is farther south than the area you mentioned. Last month, we saw beautiful color on Monarch and Marshall Passes during the first week in October, but the color in the San Juans around Ouray and Ridgway was already past peak. Every year is slightly different, so we just make big loops in fall to find areas where it is still peaking. But, if you camp in a central location, you can always drive to other nearby areas to find peak color.
BTW, if the Cottonwood Pass Road is open by the time you are in Buena Vista (it is now closed for paving of the Gunnison County side), be sure to drive it for the colors. And, if you go all the way over it to Crested Butte, you can then take the Kebler Pass Road, which is one of the most popular places in the state for fall color. If you have a high-clearance vehicle, also don't miss taking the dirt road (former railroad grade) over Marshall Pass. You will drive through aspen groves that actually form a tunnel of color over the road.
Have a great trip!