For rough terrain a short version of the indian travois is superior to wheels. Take two staffs and lash into a V. secure your duffle to the V and make some manner of harness to drag it. You now have 2 very usefull shelter supports, hiking staffs and litter poles. Gear has a point of diminishing return. To little and we rough it, to much and we are prisoner to it's logistics. Exerience only can help lighten the physical load. I would opt for a more manageable backpack.