Lovely lower purposes.

I found it easy to relate to this story, and the feeling Ian Frazier is trying to get at. I think everyone reminices about the carelessness of our childhoods. I actually have very vivid memories of stomping on the ice at the bus stop when I lived near Chicago, much like he discusses in the creeks.
His character himself is so distant though, from the narrative, that I felt like the memoir was almost forced rather than genuine. No one enjoys forced nostalgia. He uses such large vocabulary to describe such simple moments, I think that's my problem with it. "...the joke filled monotony of his synopsis went well with the soggy afternoon, the muddy water, the endless tangled brush...the woods were ideal for those trains of thought that involved tedium and brooding. Often when I went by myself I would climb a tree and just sit."

WORDS UNNECESSARY: "joke filled monotony", "synopsis", "the trains of thought that involved TEDIUM AND BROODING"

He didn't think like that when it was happening. He's so distant from his inner child, it doesn't capture the moment at all.
I would write it like this.

"His way of describing it went well with the sweaty afternoons, the muddy water, the brush that was more tangled than our hair. The woods were perfect for endless, pointless thinking. I would just climb a tree and sit."

Or something along those lines. Frazier was a little thesaurus happy.
Later on he uses phrases like "suprious nostalgia"
hmph.

two strengths of this though:
The description of the day he realized that he was too old to just sit in a tree and think, and goof off with not doing anything. I think everyone has had this epiphany. I remember one day my sister and I whipped out our massive lego collection and started building, and about half way through we kind of looked at eachother, lost. We felt out of place.
His Adam and Eve comparison? Clutch.
I also am a big fan of the part where he talks about taking his kids fishing. Because this part, I feel, is genuine. Not being a parent, it's a little harder for me to relate to, but you can tell this is the portion of the story that spawned the entire reflection itself. This is what got it started.