I can't speak for Colorado, but I went on a rifle elk/mule deer hunt last November in northwest Montana. I stayed in a lodge, but we hunted national forrest land. My guide and I walked 5-10 miles a day, and just about everywhere we went had signs of previous hunters. This was my first elk hunt, but I decided pretty quick that my next hunt will be on private land. The only elk I saw in 5 days of hunting, were about 3000 yards away, and on another mountain. It may be easier during bow season to locate the elk, since they are bugling, but I'm no expert by any means.
The things I learned on my trip: steep downhill walking caused my feet to hurt more than uphill walking. I didn't wear my backpack enough before I went, by day 4 my shoulders really hurt. Walking up LOTS of stairs WILL help your cardio, very rarely did I get winded on that hunt, and we did some serious walking. Good luck if you go!
