Books like The Crystal Cave
Mary Stewart, Mary Stwart
The Crystal Cave is 480 pages, about 8 hours 48 minutes at 250 words a minute.
12 books to read next
How long each takes
A Connecticut Yankee in King Arthur's Court 7.3 h 
The Return of Merlin 7.7 h 
The Mists of Avalon 16.1 h 
Arthur 9.4 h 
Merlín 8.8 h 
The Once and Future King 12.0 h 
Enemy of God 7.6 h 
The Winter King 8.0 h 
The Fall of Arthur 4.4 h 
The Book of Merlyn 3.5 h 
The Saxon Shore 11.6 h 
Pendragon 8.0 h Bar height shows length. Estimated at 250 words a minute.