I just returned from the opening week of CO elk season without success. Just as mentioned, the weather was warm and the elk were silent. There was lots of sign, but the hunting was hard. I only saw 4 bulls and 6 cows. Next year I'll go in the middle of Sept. Climb stairs with your pack. I'm from LA and for about 6 weeks prior to the hunt, I would run 3-5 miles about 4 days a week and hike with 55 lb pack 2-3 x wk and climb 10 flights of stairs 5 x in a row at least once a week. I didn't have any soreness and we hunted up to about 12,000 ft and walked about 50 miles in 6 days. Drink lots of water.