I'm new to training with a pack in my prep training. I bought a Kelty Cache Hauler, and I have been carrying 50lbs plus the weight of the pack to train. We don't have anything but hills around here, and that is difficult access sometimes. But my question is this. What weight should I be training with in the pack? I keep reading about these guys that are carrying out 100 lbs of meat after a kill, and I am severely impressed. Is this what I should be working up to? Also, training for the high country: other than maybe sprinting hills or going out west to just get used to it, what can I do for training prep in the absence of mountains? I weight train, run, sprint, Crossfit occasionally, work lower body, etc., but I am not an endurance minded person by any means. I want to be in far better shape before I attempt to head into elevation changes. Thanks.