I don't work for a restaurant but I work for an upscale, full service hotel. We once lost power for 2 days and we had a generator that kept the food cold. So maybe some of the restaurants don't have to re-stock?
It typically takes a day or two to get a food order, although if the whole town needed orders, probably longer.
I used to work for a conference center and we would do wedding etc constantly. Our freezer and controlled temp storage was all powered by huge generators so unless we lost power for months and there was no more fuel, we didn't lose food.
We got food deliveries three days a week and alcohol deliveries twice a week and we had a secondary vendor for all items.