I live on Long Island where it is flat flat flat. I started in the gym with weights, upper 2x/wk--lower 2x/wk and 6 days cardio walking on the treadmill with a weight vest starting with 20 lbs for 20 mins. I had to start really slow, almonst died in July. In January started taking my pack to the gym for 1 hour walks on the treadmill with up to 40 mins at max elevation on the treadmill and doing trail walk of 2 hours. With my hike starting March 3rd, I have backed of a little on the weights and concentrated on walks with the pack in the 4-6 hour range 4 times a week loaded with 35 lbs. I used to live in NYC, you could surely turn some heads bounding down the avenues with your pack on. Having the pack on is a key for me. It has given my body a chance to get used to the stresses the weight puts on my joints from those unique angles. At 52 and a former competitive athlete for 20 years, starting slow is definitely tough, but I am convinced if I don't let my body get acclimated to the stresses of the trail I am bound for injury. Good luck with the training and the walk/run.