A school bus is just a very long truck.  It rides hard.  Its suspension lacks the silky smooth, isolated feel of a coach.  As a result, stuff rattles.  Care needs to be taken to see that tables, sinks, shelves, metal panels, and every other item that is attached to wall, ceiling or floor, is attached firmly and in such a way that it does not rattle or shake excessively.

The first time we took the bus on the road - a relatively smooth highway at that - we were amazed at the cacophony of noise coming from various places.  The sink boomed.  The stainless panel behind the stove was as loud as a dozen schoolkids.  Every loose item that was not packed with soft care rattled like a banshee (although not being Irish, I have never met a banshee).

Keep the rattles in mind when you build your bus.