Isobelle Carmody books in order
4 books in the catalogue, about 33 hours of reading in all; the shortest takes 5 hours and the longest 14 hours.
1 series in the catalogue.
Obernewtyn Chronicles
6 books
Obernewtyn 4.6 h 
The Farseekers 5.9 h 
Ashling 8.7 h The Keeping Place length not known
6 The Stone Key length not known
The Sending 14.1 h