This is how the buses ran during our stay Thanksgiving Week:
Mornings - PO-FQ, then POR West, North, East and South. The buses only bypassed a depot when full.
Afternoon/Evenings - PO-FQ, POR South, West, North and East except for the Magic Kingdom which has two different depots for the resorts.
We always waited at the West depot in the mornings and never got on a full bus. Only one morning did the bus have to bypass a depot and that was on Tuesday going to the Magic Kingdom and we had to bypass the East and South depot. But the way the buses were running, those folks left behind did not have long to wait.