I'm still trying to decide what I want to say about this book. And, can I say what I want without including spoilers? 
 I keep comparing it to McCarthy's The Road, a bit unfavorably. I haven't figured out why yet, but while I was wrecked by the tragedies endured by the characters in McCarthy's book, each setback faced by Jack and Ma in Donaghue's book made me mad at the author. In the former, I was absorbed by the setting and characters. In the latter, I was always aware of the author and the construction of the story, aware of the author as manipulator. 
 Still mad.