Pride and Prejudice and Zombies. That is, of course, assuming she has read Pride and Prejudice.
It's an unusual spin on the classic romance and can be found at Barnes and Noble, Book Star, or any book store, really.
Your mother seems like she has taste, and it would be an insult to recommend anything but a classic. Austen, Dickens, these Victorian authors are good, but can get very dull. Add some Zombies to the mix and it is both humorous and classy.