las has given you some good info.
I agree 100% on those cheesecloth pieces of crap bags. I use WalMart laundary bags. They're $5 or $6 each and I use 4 on an elk. You can wash and reuse several times over.
If you bone your elk out, make sure you don't leave the meat in the bag in a big lump when you get back. Spread the meat out at night so it'll all cool. In a bag, it'll stay cool once it's cool, but until then, it keeps the heat in. Same goes for a cooler -- it really should be called an "insulator" because it'll keep the cool in AND it'll keep the hot in. Use lots of ice if it's warm, but be sure and keep the water drained off as you don't want your meat sitting in water, cool or not.
