The most optimal in my opinion:
Quest hall, Portal room, Chapel, Study room= MUST BE NEAREST TO ENTRANCE
Quest hall = Quick free glory teleport
Portal room = Quick free teleports
Chapel = Quick prayer exp
Study room = Quick teleport tablets
So you'll be using up only four spaces, and all the good stuff are already there, right near the entrance!
You can build a costume room to store your clothing, but don't place it beside the entrance, since it's not as useful compared to the others.
Don't bother with the rest, they're just fillers.
EDIT: I forgot to mention. Less rooms = Less loading time. So if you're one who wants things fast, go for my 4 room idea. If you ever get to see my house, you'd notice a 1 milisecond load before it gets to my house, unlike normal furnished houses in which it takes over 2 seconds to load.
Go for my plan. But if you already changed the skin to anything else than the default one, you still will get the slow loading screen, but it'll not be as long as if it was fully furnished.
EDIT2:
