I think much will depend on the gear we have — a pack this small and light won't work for all occasions.
This pack 'should' work for an overnight or perhaps even a weekender in temperate climes.
I would slip in two 3/8" blue foam pads plus a 3/4 self-inflating pad. These will take up one inch or so together.
Next, I will shove my down sleeping bag to the bottom. I would not use a stuff sack as the resulting "bread loaf" does not translate to efficient packing. Better to just let the bag conform to the insides of the pack — self compressing as you load up more stuff.
The rest of the pack will be filled up with sleep wear, one insulation layer, food, and misc. gear (small cookpot with stove inside, etc.).
Finally, I like to hang my tent on the outside — so I would add two bottom compression straps to the pack. Also on the outside will be two bladders in the side pockets (one fitted with hydration tube), and a rain jacket in the outside front pocket.