After searching the web it seemed that the last week in September would be the best time to catch the aspens turning in Maroon Bells. Those suggestions were right on the mark, we saw some really good colors in the mid-section of the state. Elsewhere, the aspens in Rocky Mountain National Park had already dropped their leaves and the ones down by Durango were still green.

Here's a list of the cities we passed through
Leadville -> Aspen -> Carbondale -> Cimarron -> Ouray -> Durango -> Sand Dunes -> Salida -> Colorado Springs