Books like Halt's Peril
John Flanagan
Halt's Peril is 416 pages, about 7 hours 38 minutes at 250 words a minute.
6 books to read next
How long each takes
An Ember in the Ashes 8.5 h 
Dorothy Must Die 8.3 h 
A Torch Against the Night (An Ember in the Ashes) 8.8 h 
Poison 5.2 h 
Crystal Kingdom 7.8 h 
Toby and the Secrets of the Tree 7.6 h Bar height shows length. Estimated at 250 words a minute.