I am just scanning thru the advices to this hiker and surprised to see that there is no mention of acclimatizing ahead of the hike by spending at least one or two nights at Cottonwood Camp ground at 10000 ft and doing some day hikes in the surroundings which should alleviate all concerns of AMS. This definitely helps in my own experience.
Regarding head phones during the hike, its the same as wearing head phones on a bike ride. You miss the beauty of the surroundings, the natural sounds and the great views for which you originally planned this outing! It may be dangerous if you cant hear a rolling rock or rock fall or some one shouting at you to get out of its path! My 2c.
