I have been looking for the same exact thing for an upcoming trip.
My question is, how comfortable are these little "stuff sacks with string shoulder straps" for extended day hikes from base camp? Carried load would be 1-2L of water, some snacks, rain gear, small first aid kit, light insulation layer, camera, and a map.
The OR Dry Comp Summit pack looks nice as it is waterproof (would be beneficial when kayaking) and functions as a compression sack. It may have a little too much volume though. I am also considering the REI Flash 18 and EMS Packable Pack.