Jim- I think my GoLite Quest is 4,000 cubic inches. I do 10-day trips, with a bear can, outfitted for temperatures below freezing, raingear, Tarptent, and get everything inside the pack (except crocks and water bottle). The bulk of clothing is also dependant on the size of the person - I suspect my clothing is half the bulk of yours, simply because I am short and you are tall; I probably need a third to half less food than you do. I use compression sacks for clothes and sleeping bag. All food fits in the bear can. We little folks can get by with less volume in our packs.