Books like The Mystery of the Wild Ponies
Gertrude Chandler Warner
The Mystery of the Wild Ponies is 135 pages, about 2 hours 29 minutes at 250 words a minute.
12 books to read next
How long each takes
Paint The Wind 6.0 h 
Sierra 2.4 h 
Chester 1.2 h 
The Bad Beginning 3.2 h 
Kristy's Big Day (The Baby-Sitters Club #6) 2.8 h 
Into the Gauntlet 5.7 h 
The Viper's Nest 3.2 h 
The Reptile Room 3.5 h 
The Wide Window 3.9 h 
The Scorpio Races 7.8 h 
The Miserable Mill 3.7 h 
The Emperor's Code 3.6 h Bar height shows length. Estimated at 250 words a minute.