The Tree House would be cool, but the Castle would be magical.....
if it was cold I would pick out a house in Pirates, if it was nice out I would most likely spend the night in Splash Mountain. What would be awesome is if I could be shrunk down to size to fit in one of those amazing tiny houses, they are in an outside area of Splash right before you get a good castle view.
I also liked a PP's idea of the children's beds in Peter Pan. I would enjoy looking out their window over the city of London.
Well my sleeping quarters would be the castle suite of course. But i would obviously wander around(certainly break into the Main street bakery,plaza ice cream, and main street confectionary) Only if all the lights were on of course i'm afraid of the dark
In the treasure room in POTC of course.
On Cap'n Jacks knee
BUT I can guarantee where I would NOT sleep......IASW