I would caution against over training or rucking with too much weight. I wouldn't go over 80lbs.
I would say get in the best shape you can. Strength, muscle endurance, V02 max, flexibility, etc.
Thanks, JH. That's a good point about rucking with too much weight. I have heard trainers say that training fully loaded will cause more harm than good. And to taper off the training as a big hunt approaches.