Personally, I liked the system described in Reamde, wherein the characters would become NPCs with patterns that they'd execute while the player was offline.
First they'd return to their home area, if they weren't already there, then they'd go through a basic day/night schedule, working during the day on jobs set for them by their players. Basically, when you're offline, they're acting much like something out of the Sims.
Gives people a reason to band together and build a safe town, to react to enemy raids, etc.
PFS already has the Day Job system in place, I see this as a natural extension of that. Your character simply does his Day Job and collects a bit of gold from doing it.
Obviously this system needs limitations, if you've got a blacksmith and you don't have a decent supply of coal or iron, they'll stop working til you log back in to arrange a resupply, or someone else from your guild does.