As mentioned, it is kinda a******shoot on the colors. Like Thunder Mountain we lived in Estes but not as long as he did. We used to call Sept and Oct as the season of the newly weds and nearly deads. Great time to visit.
But we will once again be back in the southern part of the state this year... Mancos (Mesa Verde RV Park), Vallecito Lake (Blue Spruce) , Buena Vista (Valley Rv Park - first time for us at this park), Montrose (KOS), Ouray (KOA) --- leave 9/3. But heading to Capitol Reef in UT to be there third week in Sept for Escalante Staircase aspens, down to Bryce again, a day a Zion again and the Grand Canyon and home). So we will most likely be a little early for the peak colors in CO.
Hey, if you get to B V you will want to drive up to St. Elmo. Some call it a ghost town but they like to call it a restored town. It either case well worth the drive.
Western CO is beautiful most anytime but in the fall it simply cannot be beat.
Enjoy