To be honest, I think my character (Murielle) would love a treehouse with a lot of hidden rooms inside and a deep dark basement under the tree that is... If anything terrifying. The tree would be old and warn down but still amazing to live in. As well as being large, it has a homely feel in the main rooms with some questionable feelings coming from the other hidden rooms. I have a feeling it would not look like a house on the outside either, just looking like a regular tree to keep her home hidden. Either surrounded by forest or in the corner of a district.