Hiking in Colorado at that altitude is a different animal. Me and a group of guys from my church did 24 miles in three days & nights in the Collegiate Peaks area of the Colorado Trail near Buena Vista/Salida end of last June and it was an absolute blast, but I was sucking wind almost the entire time and kept fighting off the urge to vomit. I was carrying a 35-lb. pack and taking Diamox for the altitude sickness. We were able to summit Mt. Belfort (14,207'), and if we had enough time we could have grabbed Mt. Oxford too, but we had to split the last day. That last night we camped at 12,500' elevation, and it was the absolute clearest night of stars I've ever seen in my life. Total climb across the 24 miles was about 7,000 feet.