Osprey packs can handle just about anything, it's all about what you can handle safely. This bag will easily carry a 60-80lb load, but I'd suggest lower than the lower end of that scale considering your frame and back issues. The weight will be distributed evenly and as comfortably as possible with the design of this pack, I'd just test the waters and see what you can carry comfortably and use that for a reference before going out and purchasing such a large scale item. They have it in smaller cu in sizes.

I work as a mountain guide in New Mexico and Colorado and we recommend that no one carry over 1/3 of their body weight. This puts excess strain on the spine and can cause it to compress on extended (over a week) trips.

average is different for every person but this pack could handle 50-60lbs. Osprey makes good packs so it will be stable.

This pack is awesome, but for what you will be carrying it might be a bit heavy. Osprey carries something called the Aether 85 which is an 85L pack that I am sure will do the job, and it weighs almost 1.5 pounds less.

REI and Eagle Creek make some "travel backpacking" packs that might be more what you're looking for.

First, doing Europe with the backpack rather than suitcase is absolutely the way to go. This is the sort of pack that you should buy for a NOLS course. I would do something different for backpacking Europe. We have used packs that are more geared for "travel" rather than backpacking. They typically have zip off day packs and fewer straps and/or a zip over cover for the hip and shoulder belt so you don't need an overbag to check it without worrying about it coming out of the baggage area missing a shoulder strap.. Osprey makes some targeted at this application.. I have found it better off to organize in stuff sacks/cubes rather than have a lot of pockets on the bag, but that is my organizational style. Good luck. Also might look up Rick Steeves on the web - best "low to the ground" travel guides and his site will have more advice about bags.

How long of a camp are you going on? This wouldn't be a bad pack but you might also check out the Osprey Exposure 66.

The Osprey Switch series of packs aren't nearly as large as the Argon series, but they are specifically designed for snowsports. You can attach skis, snowboards and snowshoes with ease. However, these packs are designed for day trips, so that might not be what you're looking for.

This expedition pack is not available in a small size.

One zippered main pocket. The top compartment converts into a lumbar pack.

The "High-Tenacity Nylon" pack material is water resistant to a point. I would not recommend exposing any pack to sustained rainfall for prolonged periods of time without water intrusion occurring. The addition of a pack cover would definitely be beneficial in this case.