Honestly, the best way to train for a sport or activity is to actually do said activity. Your body adapts to specific movements rather quickly, which often do not translate to other movements well, regardless of your athletic ability.
For strength, any weighted workout that builds your leg and hip muscles efficiently is best. Regular A2G squats, Sumo squats, dead lifts, split squats, lunges, side lunges, and calf raises. It doesn't have to be fancy, or some "hunter-specific" gym workout...things that may actually delay the gains you could be achieving. You're looking to add a strength foundation, and be able to sustain the workout for a reasonably-long duration.
Pair that with hiking with your weighted pack through actual terrain and varied footing will get you the best results.
Simply rucking down a sidewalk with no obstructions, or on a stair stepper where your feet only have to clear the same level step each time certainly helps some with cardio, but does little to work your feet, ankles, legs, hips, and core in the same manner as having to adjust footing, constantly step at varying heights over obstacles, and shift weight from one side of your body to another to keep a proper base on uneven terrain...the factors that will burn you out far quicker than your body's ability to simply endure moderate repetitive activity for a few miles here and there.
To relate martial arms, simply because my family does it, there is no useful "MMA-specific" weight-lifting exercise. Meaning, you aren't going to pick up a set of kettlebells and do some dynamic thing that will appreciably move the needle for you. Pure weight lifting is far more efficient from a strength perspective, and time dedicated to any such program is better spent doing the thing you're trying to get better at for longer.