Jason Francis wrote an answer about Osprey Packs Aether 70 Backpack- 4000-4600cu in on April 4, 2010
Ariel 75 was the winner. Just enough space--including the camera gear --for my long weekend trips. The 67 might work with a smaller cooking system or tent than I have though; strapping the canister to the outside would also work but I decided against that because of steep scrambling situations I find myself in 50% of the time! Good luck longhiker.