Nothing wrong with GOMAD, if you aren't allergic. Caloric surplus is mandatory for strength increase (generally speaking), unless you are wearing a substantial caloric surplus.
Also mandatory: a deliberate effort made to rest and recover from the training. This means sufficient sleep, and minimizing or eliminating activity that will rob resources needed for recovery. If you are a house framer or drywaller or timber cruiser, that activity may interfere somewhat with your strength increasing efforts, in spite of you being already adapted to your job. The strength work will still be seen by your body as additional stimulus, however, and with sufficient rest and caloric surplus, you'll get stronger and bigger.
As I've harped on before, though, the big problem with strength gain is perception. Folks believe that you'll get all bound up and worthless for a long haul if you dare to put on 30 lbs of muscle or more. Nothing could be farther from the truth. You can't neglect the toughness of your feet when training for hunting. You can only train foot toughness by hiking uneven terrain in your boots. Heels going uphill, balls and toes going down, ankles on sidehill. By the time you've trained to where your feet are tough enough to recover normally (overnight) from a hard hunting day, your "cardio" training has taken care of itself, and you've shed the 20 lbs of fat that hitchhiked aboard with the 30 lbs of muscle last winter when you made a focused effort to get strong.
