I think it's probably worth pausing to understand just how far apart things are in the American West, as it can be a bit hard to grasp when you've never been in the west.
This is probably the best bit of perspective I can give:
The distance from San Francisco to Colorado Springs is about 1325 miles.
The distance from Newark to Kansas City is only 1175 miles.
So while its easy to think about looping in San Francisco and Los Angeles with Colorado, what you're talking about isn't all that different than including Kansas City or New Orleans in with a trip to New York and Boston.
Which isn't to say that couldn't be done within 2 weeks, but it's a lot of miles - and time to cover those miles - that you need to take into account.