My daughter has only been collecting the dolls/books for a few years. So far, her favorite books go along with the girl of the year dolls. There's always an introductory book and then 1-2 follow up books for GOTY. She's read and loved:
McKenna- 2 books
Saige - 2 or 3 books
Isabelle - 3 books
Grace - 3 books
I don't really know much about Beforever--sorry! I just think they go with the dolls that aren't girls of the year?
My reading non-lover really enjoys these books.