This was a really good series, which I would definitely recommend for girls around age 11 and up. You can sometimes find them at Christian book stores or here
“This five-in-one volume brings MANDIE fans–new and old alike–back to where it all began. Readers will discover anew the charms of the impulsive Mandie Shaw as she faces the ups and downs of first losing her father and then finding her long-lost family in “Mandie and the Secret Tunnel.” Many more mysteries follow for Mandie and her friends in “Mandie and the Cherokee Legend,” “Mandie and the Ghost Bandits,” “Mandie and the Forbidden Attic,” and “Mandie and the Trunk’s Secret.” -via www.bookdepository.co.uk
And while not very close to the original stories, there are three Mandie movies, available here
which, I think are still enjoyable, though make sure you have read the books before watching.
Also if you have read the series, please feel free to leave a comment, I’d love to know what you thought of it .