My program's design is to build strength, not necessarily endurance. I add five pounds a work out as long as I can perform the exercise with good form. (5 sets of 5)
Should I change to endurance work with the weight lifting? What kind of reps/sets?
Or would it be better to keep with the heavy lifting with low reps and just do more wind sprints, Tabata, etc.? Say sprints three times a week and tabata every other day?
Depends on your goal. Doing a bunch of cardio will slow down strength gains, but you WILL continue to get stronger, if you do the proper work and provide for recovery. Recovery is KEY, and this is where a bunch of running will screw you up. Powerlifters do brief, intense cardio, like pushing a Prowler and doing tire flips.
Crossfitters would say lift heavy, lift long for endurance, run long (occasionally) and do a BUNCH of 400's and 800's. Crossfitters will never win a powerlifting meet, doing Crossfit.
Crossfitters say that you have to do it all, because you never know what life will toss in your path. Well, a hunter does know when the season is, and he knows where he's going, and what he's going to carry, for the most part.
The primary focus of your training, for maybe six weeks or so before the season, should be walking with a pack in a manner that simulates what you plan to do. For instance, if you'll be chasing critters at high altitude and covering LOTS of miles. You'll be better served by upping the mileage on your ruck walks. If you plan on a two mile pack out, alone, of an elk. then doing shorter walks with a heavier pack 2-3 days/week, combined with a couple of squat workouts each week are in order.
IMO, Crossfit is the baseline, IE, this is what you should be doing at least half of the time. For a hunter, doing a round of heavy weight training like Greyskull or Starting Strength at the first of the year for 6-8 weeks, right up until your strength gains stall, then going back to Crossfit until you start your ruck walks in preperation for hunting season is the ideal plan, IMO.
