Wolf has a flair for setting the atmosphere here: the bitter cold, the piercing hunger, the total desperation that they all felt is in turn felt by the reader. I also liked the choice of having multiple narrators (though the Hunger narrator could be a little didactic at times, but considering the intended audience is younger, that's understandable) and appreciated that no one was portrayed as a total monster or hero. All of the information in the notes section was great, too. All in all, an informative and emotional read. 3.5/5, bumped up because Buck and Bright were the best boys.
Also, I don't like even being mildly uncomfortable, so I wouldn't have survived long in the Donner Party or basically in any other time in history. Being cold? Experiencing even a slight amount of hunger? No thank you.