I have a bag from cabelas that allows me to lash the bow to it. It's a heavy setup if you are also carrying a climber tree stand. Figure a good 60lbs on your back, and you learn quick to K.I.S.S!
I retrofitted my treestand to work with a Molle system. Lash the backpack to the treestand, and carry the bow in your hand. Don't have a heart attack in the process