This is my first experience with the Jason Strange series, which has lots of advantages for young (and possibly reluctant) readers:
A short book with short chapters
Illustrations
Good pacing
The creep factor is pretty high for a book for young readers. There's no gore, but the build-up and the scares were much better than I had anticipated. If you have a young reader who's maybe not quite ready for The Last Apprentice series, the Jason Strange books might be just what you're looking for. The book also ends with "case file" notes, telling readers that this is just one tale in an ongoing series. It even includes a few discussion questions and writing prompts for aspiring young writers.
I surpised myself and liked this book. I thought it might be too creepy but it just has a great mystery ending. Highly recommended for 2nd, 3rd, 4th grade students.