How does Krakauer characterize Walt McCandless?

What chapter are you referring to?

I think you are referring to Chris not keeping in touch with his family. This is perhaps Krakauer's biggest criticism of Chris. Krakauer admires Chris's adventurous spirit and his counter-culture values. He, however, laments Chris's selfishness towards his family for basically disowning them. His parents did not deserve the grief and hardship that Chris caused them by not telling them where he was and what he was doing.