I do R&D for a backcountry company. What I find helps me the most is Olympic lifts, heavy squats, strongman training and especially HEAVY sandbag getups.
I train everything EDT style.
This past summer I fractured my foot. I usually rely on mountain biking and hiking for my cardio. I did significantly less cardio coming into this season and I'm a whole lot faster on the skintrack than past seasons. As much as 45min. faster on "Worker laps".
I think max strength is the most important quality to train for followed by armoring.
Sorry, I don't know anything about Crossfit other than it's injury rate is obscene.