So the first major misconception I have seen is the notion that the best way to train for backpacking is....to backpack! WRONG.
While you are certainly not doing yourself any harm or disservice by training that way, you are not by any means maximizing the efficiency of your training. Consider this...if you live anywhere below, say, 3k elevation and then travel to 8k+ elevation, literally everything you do will be harder at 8k than it was at sea level. So, if you are training for a hunt by simply replicating as close as possible the activity you will be doing at elevation, you are setting yourself up for disappointment. Hiking at elevation will always be harder than climbing stairs at sea level. Even if you are doing it with increased weight at sea level.
The goal of any successful training program is to train at intensity levels that are significantly HIGHER than your actual activity. I don't want to be dismissive, but backcountry hiking/hunting is just strenuous walking. There is almost no skill whatsoever to the activity. We all do it everyday (hopefully) and our species has literally evolved to be efficient walkers. We are physiologically designed to walk. Not stand, not sit; walk. All of the skill in hiking/hunting pertains to non-fitness items (following a trail, map reading, reading/recognizing game sign, general mountain safety, survival skills, packing technique, etc.).
I said earlier I am new to hunting...I am not new to hiking/camping. The most strenuous hike is not nearly as cardio intense of an activity as, for example, playing full court basketball at full speed for 1-2 hours. Or climbing several thousand feet of singletrack MTB. Or playing a couple intense games of ultimate frisbee. Or kayaking miles of rapids, etc.
Training your cardio system by any of the above mentioned examples will absolutely have your cardio capacity at a higher level than simply rukking. Again, no argument against incorporating rukking into your regimen.
Just saying, if you think for a moment that a college basketball player couldn't throw on a 40# backpack and hike for 5-10 miles with ease, or if you think an amateur cyclist couldn't hop off the bike and run a 10k at a pretty fast clip without any "specific" training, you have misread the literature.
At the end of the day, backcountry hiking/hunting falls into the general fitness category and will have very significant benefits from all forms of cardio training. There is nothing especially unique or demanding (other than altitude) about hiking that requires you to hike as practice. The reason basketball players practice by playing basketball, or boxers practice boxing, or sprinters run sprints, rowers row, etc. is because they are practicing the unique skills, technique, form, etc. that is demanded by their sport to be at the elite level. None of that applies to hiking. It is just basic strength, cardio, and balance.
Which brings me to the second misconception....strength training.