Opt for the more expensive bags that resemble coarse pillow cases. Bag all of your meat before you take your first load back to camp. If the animal died in the brush, move the meat into the open, away from the carcass. Bears like to eat the skin and guts first and prefer shrub fields. Line your pack with a plastic bag, put in as much weight as you can safely carry, and head back to camp.
Some hunters bone the meat to minimize weight.
For trophy meat you should avoid boning whenever possible. It exposes more of the meat to insects, bacteria and drying, and makes it harder to hang and age it properly. When you get the meat to camp, hang it in a tree, on a rack, or in a small stand of alders. Your hanging area should be close enough to your camp that you can see it, but not so close that a bear could cause problems. If you are rafting, devise a rack to keep the meat off the wet floor.