How about going old school? Peanuts, walnuts, cashews, beef jerky, dried cranberries, apricots, brown rice, quinoa, bulghur. Plenty of calories, protein, fat and fiber, reasonable shelf life, and healthier than the highly processed faux foods. Most of this stuff is available through Costco or sams club, avoiding the marketing mark-ups at outdoor/surplus/zombie apocalypse emporia.

...and lots of chocolate, cuz if I eat an exclusive diet of squirrel food, I get a littel squirrely.