In the book Into the Wild by Jon Krakauer, how effective is his organization?

I am going to assume that you mean Jon Krakauer's narration of the novel.  

I think his narrative organization is functionally effective.  While the story does seem to narrate in a haphazard manner, the narration of Chris McCandless's time spent wandering is, for the most part, in chronological order.  

The main exception to the chronological story telling is found in Chapter 1.  McCandless is already in the Alaskan interior, and he is riding...

I am going to assume that you mean Jon Krakauer's narration of the novel.  

I think his narrative organization is functionally effective.  While the story does seem to narrate in a haphazard manner, the narration of Chris McCandless's time spent wandering is, for the most part, in chronological order.  

The main exception to the chronological story telling is found in Chapter 1.  McCandless is already in the Alaskan interior, and he is riding with Jim Gallien.  Jim is the last person to see Chris alive.  I appreciated Krakauer's attempts at walking his readers through an organized interpretation of what he believes Chris did during the time before his death.

What I found particularly jarring in the text was the constant interruptions to talk about other people that Krakauer believes are similar in spirit to Chris.  I grew to appreciate the similarities that were being drawn, but I never enjoyed being pulled away from what Chris was doing.  Perhaps Krakauer did that on purpose to help build tension?  

While annoying to me, Krakauer's interruptions never felt out of place.  The comparisons always fit well with what Chris was doing.  So in terms of pure organization, I think Krakauer did a fine job.  But that doesn't mean I have to like the way that Krakauer organized it either.