Forget the game cart idea-I have one for deer & even that can be a hassel in a lot less rugged country. If you have to bring out without horses bone it-get a good pack frame. No matter-you have lots of work & usually several trips if no other help. We have had to make 2 trips with 3 making the 1st.
No easy way around backpacking out meat-BUT, it is " DELICIOUS" .
good luck...