If you could move your trip at all to the 1st of May or so, I would.
April in Colorado is a "dicey" month. It could be beautiful, but more likely than not, it will be muddy/snowy/rainy/all of the above at least part of the time.
Springtime in the Rockies is very unpredictable. We get the most snow along the Front Range in the months of February, March, and April.
That being said, I live just north of the Air Force Academy, so I can recommend some things to see and do in the region, as well as some Colorado Springs restaurants.
Could you give me a little bit more information? Do you have kids coming and what are their ages? What kinds of things do you like to do?
If you prefer, feel free to p.m. me.