Lemony Snicket S. of Unfortunate Events.
The following are very good, but more realistic fiction.
Boxcar Children
Nancy Drew
Trixie Belden (ideal for slightly younger kids)
Elizabeth Enright's books-- Gone Away Lake, Thimble Summer, etc.
Lois Lowry has some very good books with female protagonists as well.
Hermione Granger, Luna Lovegood, and Ginny Weasely are pretty strong female roles in the Harry Potter series. There are some strong female protagonists in the Mistmantle Chronicles and in the Redwall series, too. Those would all be appealing to a girl with this set of interests. The Warriors books will, as well-- I'm sad to say. Those books are really dreadfully written, unfortunately, but there's a reason that so many girls find them so appealing. So much high fantasy is about boys-boys-boys.
Watership Down? (Might be a bit much for her manage right now in terms of emotional content-- it is quite intense.)
The Spiderwicke Chronicles. This would be just about ideal, I'll bet.
