I hope these compressors you guys are using are quiet. My father has a direct drive oil free compressor that could wake the dead. Your neighbors would probably rather you start the engine than use a compressor like my dad has.
I have one of those generic 120 VAC "2 HP" twin-tank direct-drive oil-type compressors that are available under a variety of names from different vendors. It's connected to the bus's accessories tank that is isolated from the rest of the bus air system by a PR-3 valve - this way it will not affect the brakes' air supply. In an emergency I can also connect it directly to the wet tank and air up the entire bus in less than ten minutes. I chose the twin-tank style of compressor because it's lower than most others and it fits neatly in the luggage bay under the frame rails. I also put three air outlets around the bus, good for inflating tyres and using air tools. So far so good.John