And, what's the difference between 部屋 and plain old 室?
Simple! 部屋-pronounced-wrong is an average house-type room. Anything else with a 室-pronounced-correctly suffix is a specialized room.
Get your SHIT out of my room! Jesus!
You can't wear the crown until you get to the throne room.
You go to a mortuary store to buy a CORPSE,
but you wear a CROWN in the throne room.