Looks like Broomfield has a bit of a milder climate than Bozeman, but I'll throw in my 2c. I think a cyclocrossish bike would be fine, provided you get winter tires (either studded or dedicated winter tires.) If it does get icy, you're going to want studded tires. With studded tires riding on ice is as simple as riding on asphalt. Also you're going to need some cold weather gear. Check out the winter forum for lots of suggestions. I personally ride a mountain bike in the winter, but that's my preference.

Otherwise, the other three seasons shouldn't be too difficult for you. Sure it'll be a bit colder, but that's not usually a problem.