Gutless is the way to go. I've done 3 moose and and an elk so far gutless. If you need to quarter, there's no reason to gut. The moose hindquarters are heavy, so I always take one of those plastic snow sleds. If there is snow on the ground or fairly flat ground, strap in 2 elk quarters or one moose and away you go. Downhill is the best route if you can, even it it means twice the distance. Keep the skin on if it's dirty, otherwise use good game bags.
Also, sometimes deboning helps with the weight if backpacking, but I like keeping the meat as whole as possible. When I hang up the meat, the hard film that develops and covers the meat keeps dirt, bugs and protects the meat. There's usually less trimming when with larger pieces than trying trim a bunch of smaller pieces. But what the heck, everyone figures out what works best for them.
12 miles is a long way, arrange for horses beforehand.