I also liked the fact that Abby wasn't in the adventure with her brother and dog, but had three of her associates from school with her. The friendship triangle is a HUGE problem for late elementary and middle school students, and it is something many readers will have had personal experiences with. Penny, with her mansion, nanny, and absent parents, is a bit over the top, but who else could steal Robin away from Abby? Frankie is delighfully scatter brained, and Abby is tense not only becasue of Robin but also because she doesn't know how to explain the adventure to her friends!
Twisted fairy tale stories are always in demand, and this jaunt into literary fiction opens up the series to many other avenues. Will Abby visit the prairie with Laura? Go to Prince Edward Island with Anne? This would be a good way to introduce young readers to some classic books in a fairly painless way. Hand this to readers who like this series, Buckley's The Fairy Tale Detectives, or even Townley's The Great Good Thing, where a reader is able to enter a book.