RE: What do you carry in that Backpack??
I'm a fanny pack man.
I carry my knife, powder wind checker, fine thread wind checker, surveyors tape (aprox 5'), compass, thermacell and refills, backup release(don't forget to practice with it guys), a variety of scents, chap stick, extra pull rope, tree stand stabilizing strap, head lamp,very small note pad and pencil, food and waterbottle(for all day hunts only).
That about sums it up.