Hiking Half Dome is on my "mid-life bucket list." Any suggestions on the best way to train? What should I be able to do before getting there to "ensure" I am prepared not just to survive, but to enjoy the journey. I realize I need to actually hike to prepare, but in terms of getting an objective sense of things, try to make suggestions based on "gym-training"-- how much/long long should I be able to do a stair master? Treadmill? Etc. etc. Any pointers would be most appreciated! THanks!