Alaska law requires you take all the meat from the outside and from inbetween the ribs too, also that "all the meat" is packed to camp BEFORE the horns are packed in!! Of course, you can pack the horns in with the last load of meat.
I always boned out the animials i shot, and that's because 99% of my hunts were by plane, and we needed to get things as light as possible. Seems there's NEVER enough runway in the bush!! On the water, or gravel bar, it's always a fight to get as much off the ground as possible.
When boneing an animial out, i cut the hide down the back, peeled it to the stomache, and took all the meat off as i went. When i wasn't useing a plane, i sometimes did it other ways, but i like boneing in the field.
Drilling Man