My youngest dd is 9 and also an advanced reader. She is reading the Kingdom Keeper series and Harry Potter now, but I don't think she'd have gotten into either series at 6. Not Disney related, but my dd and my ds7 both like the Magic Treehouse books series. The Hank Zipzer series, written by Henry Winkler, who starred in Happy Days, is also good. He writes about his life as an elementary school kid with learning issues and it's pretty funny. I teach special ed and I liked it, my class just thought it was ok. Another good series, which I've used in my classroom, is written by Carole Marsh. It's about a set of grandparents (Carole and her husband), who take their 2 grandkids to places all around the country and the world. They always meet up with kids from the place they're visiting and have a mystery adventure. Her earlier books featured her son and daughter, rather then grandkids. The kids are elementary age in the stories. She's got several series out now, the original one I think was listed as Carole Marsh Mysteries. One of the books is set in WDW. My older dd's read them up until this year and they're 13. Note to self: find Carole Marsh mystery books for younger dd!