The space would required quite a few emergency (battery) lights. Normally I would eliminate the battery emergency lights and connect some of the building light fixtures to "emergency circuits". In this case however the distances of the emergency feeders would be significant. (100A feeder) about 200 ft from the generator to the transfer switch and another 400 ft to the other side of the building.
So instead of the emergency lights we would have:
600 feet feeder.
Two 100A panelboards.
100A transfer switch.
What ever the additional cost of the generator to make it emergency (instaed of just standby).
