What about Nancy Drew? I'd suggest Trixie Belden but apparently you can't get them in ebooks, which is a shame. Hrm.
Has she read Peter Pan and Wendy, Alice in Wonderland, Through the Looking Glass, Heidi, The Secret Garden, The Brothers Grimm Fairytales, The Story of Doctor Dolittle?
Librivox has a list of PD childrens works here:
http://librivox.org/childrens-literature/ the pages should have links to the free texts as well as the audiobooks they've made.
Edit: Also. Black Beauty, A Little Princess... I was little not so long ago, I should be able to remember more. I'll think on it. XD (The benefits of being nineteen ><; you remember the books you read as a kid easily)