When you need to portage your gear more than a quarter-mile or so, you want a bag you can haul like a backpack. The Boundary comes with a removable suspension system designed for medium-size torsos (around 18 inches). We filled the bag to 30 pounds and the carrying system eased gear-hauling immensely (though we wished for a thicker waistbelt).
We submerged ours and the vinyl bag kept everything dry. Available in 35-, 70-, and 115-liter sizes.
115L: $120; 3 lbs. 6 oz.