Clark's writing. He's not writing a journal. Journals are private ,hidden things. This work- it's too public, some thing one of the others could readily find. He's writing, I think, a repudiation, a confession of things he cant yet
speak of aloud. Echoes of his past miss deeds will be with him always-he must not become paralyzed with regret now so very close to crossing the mountain to a new life.
Astute observation! He's definitely NOT writing a journal or even practicing his writing abilities, even if he's still turning the idea of becoming a reporter over in his mind. It's something much more personal, but what, exactly, it is, remains to be seen. And yes, we will find out, one way or another.