Good suggestions already on stuff to bring to WY, but the big question is what to take in the day pack. I would disagree with some of the suggestions so far.
I opt for carrying very little with me. If you do many hunts, or packing, or both, less is better and more likely to be with you. Trust me, after week one, you will be looking to leave stuff back at camp. You don't want to leave out some first aid.
I carry (for first aid) only duct tape and a lighter. The latter is obvious.
I already carry a compass, knife, water, maps, rain gear etc in my pack, but those need to be handy beyond a first aid kit IMO.
Duct tape can be use as band aids and major cuts(with pieces of the t-shirt you are wearing), an ankle wrap, or splint with nearby sticks.
It also works well for non-emergencies.
There is only so much that you can prepare for out there and hence bring with you. I suspect medium falls and cuts are about it so I think I am covered.
BTW: I know bigger things can happen, but I don't believe I can do much about it. e.g. a heart attack, major fall, or frickin' grizzly having a bad day.