Sep. in Co is still quite warm, 60 or even 70 degrees although it does get cooler at nite. I use a pair of uninsulated Cabela's mountain hunters but any good brand is fine Kangaroo leather is very good. Don't think just because you are hunting elk thats its climbing all the time, most places its sloping hills and climbing over downed timber. Oh yes gore-tex is a given.
Redclub