Some of the places you have listed are really much too far apart to do as day trips from only two base points.
You do have time in two weeks to visit all the locations you've mentioned, but you would need to do it as more of a road trip, making a loop from place to place, staying two to four days in each location.
Drive from the Denver airport to Colorado Springs for two or three nights, (or spend a night in Denver before heading for Colorado Springs) then through Canon City to see the Royal Gorge and on to Mt. Princeton Hot Springs for two nights. Then, if you want to drive over Independence Pass, make Aspen your next stop for a couple of nights. Redstone could be a day trip from either Aspen or Glenwood Springs, or you could make Avalanche Ranch your base to visit Aspen and Glenwood. If you didn't want to drive over Independence Pass, you could go from Nathrop (Mt. Princeton Hot Springs--be sure to go to St. Elmo ghost town and hike to Agnes Vaille Falls while you are there) through Leadville to Interstate 70 and visit Vail on the way to Glenwood Springs, Aspen and Redstone. After that, your next stop would be to backtrack through Vail on I-70 and then: either (1) Grand Lake or nearby (or YMCA Snow Mountain Ranch) and then drive Trail Ridge Road through Rocky Mountain National Park to Estes Park or (2) back toward Denver and then to Estes Park. Your last stop could be an overnight or two in Denver for any sightseeing you wanted to do there before your departure.
With the other things you are doing, I think you could easily skip staying at Vail, maybe just visiting it for a little while on your way through.
If that still sounds like a little too much driving and moving around for you, then I would scale back your trip a little, perhaps making your three bases Colorado Springs, Mt. Princeton Hot Springs, and Aspen/Redstone/Glenwood. (You could still visit the Royal Gorge on the way from Colorado Springs to Mt. Princeton if you wish) Or, visit Estes Park, Aspen/Glenwood/Redstone and skip the more southern locations.
Edited: 25 March 2012, 13:07