The good people at MTN TOUGH fitness put real research into developing their programs specific to backcountry hunting.
It is not a gimmick. I have long made fitness a part of my life, driven largely by my desire to hunt hard, and the MTN TOUGH programs have been the best foundation for me. I used to come up with my own programs, and it worked ok, but was inconsistent even at my best.
MTN TOUGH gave me clear direction, and daily expectations and motivations to push onward.
I would recommend the 30-30 body weight program for somebody just starting out. Moving eventually to the Postseason Strength, Preseason Prep, and In season program cycle.
Think of fitness as a lifestyle commitment and not just a seasonal (or specific hunt) preparation.