Being in good physical condition is important. You'll hear lots of different stories on this. Take advice from your buddies who hunt around Pagosa Springs. They will know. Some would have you believe you need to be able to run a marathon in record time and dead-lift 500 LBS. If you can do that, it would help. But many successful elk hunters can't get into that kind of shape. Train for endurance. Elk hunting is an endurance activity. Getting through the first day isn't enough. I walk 2.5 miles every day with a 50 LBS pack (50 LBS bag of sand in the pack) and add a more intense exercise after the walk: rowing on a mechanical machine one day, strength exercises the next day (push-ups, sit-ups, dumbbell work, lunges, squats, knee-lifts, etc.). I tend to do this exercise year round, adding more walking distance and increasing the intense exercises as the elk hunting season draws closer. My regime is NOT the super aggressive marathon running/500 LBS dead-lift regime. But it works for me. Lose weight if you are overweight. Don't start your exercise routine on September 1. Start now or start on February 1, if you want to give yourself a Christmas break.
You should have good boots. You will probably do a lot of walking over uneven and rocky ground. If you are lucky, you will be doing a lot of walking over uneven and rocky ground carrying a heavy pack full of elk meat. This walking calls for stout soled hunting boots with good ankle support. I like Meindl Perfekt Hunters from Cabela's. Other suitable boots are available.
Wear clothes that can be layered and that are warm when wet. A wicking base layer (long underwear of polypropylene or merino wool or some other fabric), wool pants (can get M-51 Army Surplus wool pants cheap on-line), wool shirt (Pendleton wool shirts can be found cheap on-line sometimes), and a warm breathable parka. You may also like to have a heavy wool vest or fleece vest. You will sweat in these clothes. If they don't wick the moisture off your body, this sweat will keep you wet and make you cold. Also, you may get wet from various causes -- blizzards, rain, splashing/falling in a water course. Wool remains warm -- or pretty warm -- even when wet. It is quiet when moving through the woods. I'm not saying there aren't other clothing alternatives by the way, just providing one detailed alternative. Have a warm hat.
A .30-06 shooting 180 grain bullets is enough gun. Other cartridges also suffice.
There is a lot of other stuff involved, but you can start exercising and building your clothing stash now.