My ultralight frame pack (osprey exos) is just under 3 lb. and I'd probably top that one out at 35 lb fully loaded. A heavy duty pack that can take 50 lb loads on up will easily come in around 5 lb.
But a mile or two isn't far. For those kinds of distances, you can strap on 2 packs (one in front, one on your back) or just carry your gear in one on your back and the other, for the carcass, you can carry in your extra hand (full pack on your back, bow in one hand, extra pack in the other). If you get something, you just have to make 2 trips or one awkward trip. I wouldn't want to do it over 3+ miles but a mile or two is over and done so fast that you can get away with a lot of crazy methods.