@Frustration in Excelsis  
And now, after The Last Problem, zero people live there.

There’s no way that like 90% of Twilight’s castle isn’t just… empty and collecting dust. Between all the hallways and hallways and rooms and rooms it’s show having and the three people who spend any amount of time in it, there can’t be more than a tiny fraction that’s used regularly.
 
I mean, from what we’ve seen the actively used portion of the castle boils down to three bedrooms, a bathroom, Twilight’s library, a kitchen, a dining room, the map room and the entry hall, plus adjoining hallways. That comes to maybe eight actual rooms – this shot alone shows thirteen, and the ones from “Castle Sweet Castle” even more in clearly different regions of the castle.
 
Methinks that the Tree was expecting a lot more people to live in here than ended up doing so.

i used exif editor and made it 360 panorama for facebook.

That is a lot of doors.