Not to confuse the situation, but depending on the room, both. We were in Riverview RR at Oak Manor, and walked across the bridge to the main depot in front of the main building. My in-laws were in building 14 or 15, walked across their bridge, and we met at the bus depot there.
Oak Manor is closer to the secondary depot on the bus route, while the preferred AB rooms felt REALLY far from the West Depot... but it didn't seem to matter because that's why we used the main one in front of the main building.
Sorry I can't help more, but our trip last year was a great sample of the different rooms at POR and their locations - in laws were in AB, we were in Mansions, and we learned a lot about how to get places when we would meet up.