L.H.
I was a reading teacher, and my daughter reads in the top 1% of the nation on the Star test, and loves dark books. Poe was over her head, though, so you would have to be ready to explain a lot of figurative language. Frankenstein is also very difficult language. Step-Up books are a good choice, like the one you mentioned, but are hard to find. It is not a classic, but the Twilight series is a good scary read that is easy. We have read Tom Sawyer, Anne of Green Gables, Secret Garden, Pride and Prejudice,