[spoiler]she shows up with Tim Shaw when he returns from NY, obviously with him as part of a business scheme for which she is being well paid.  There is a scene about that time where Shaw and Quentin are talkign about I forget what and Quentin offers to wager him for Amanda's services for the evening (Victorian speak for he knows shes for sale to anyone; a courtesan).  She apparently has no knowledge of her background before a certain...[/spoiler]

I looked through my architecture books, and the house that I came across that people might be most familiar with that came closest to resembling what the Old House looked like is Biltmore, located in Asheville, North Carolina: