RE: game cart
In my experiences, the game carts work pretty good. In rough ground it can sometimes be a tough job getting a big deer out. Game carts don't do well if you have a lot of obstacles like tree logs and thick brush but overall it makes the job easier. Sometimes the hardest part is getting the deer strapped to the cart.
I also thought about using a wheel barrel but they are made to be pushed not pulled. And if you have very rough ground there is no way you will be able to push out a 200 pound deer, and even if you could it would wear you out. I would either go with a cheaper game cart or build one. I got mine through cabelas for about 80 bucks. Nothing to fancy but it works. My next job is to try and put a lawnmower self propel system on one. That would make the job a whole lot easier. Or the easiest thing is get a 4 wheeler and a trailer.