I can do a 5 day winter trip with a Osprey Atmos 50. They are good weight carriers. This past April I carried 16 lbs. of water to dry camps for my wife and I in the Grand Canyon , besides my normal load. If they fit your frame (have someone who knows how in a shop fit you), they are GREAT packs. I use to have an 85 for winter trips, but that was when I used a synthetic sleeping bag that was fairly huge. I use the Atmos 50 now, and it is big enough to strap snowshoes to and carry my winter tent. I would consider downsizing some of your gear if you can and then reconsider your pack needs. You might consider showing us a list of your gear and we can make some suggestions on how to cut back some. Not all downsizing requires large investment. A bear can will fit inside the sleeping bag compartment of the Atmos. My Garcia carries well there when I need it to.