What can you infer about the man's personality and character, based on the first paragraph of "To Build a Fire"?

From the first paragraph, the reader already notices that the main character does not follow what would be considered common sense.  For instance, in the first line, after London establishes the setting of the story as the Yukon, he notes that the man "turned aside from the main Yukon trail and climbed the high earth-bank, where a dim and little-travelled trail led eastward..."  The man already turns away from conventional wisdom, which would tell him to stay on a more known path in case of emergency, and instead, chooses the lesser-travelled one.  The man seems determined to prove himself against the elements.

There is also an instance of foreshadowing in the first paragraph when London describes the setting: 

There was no sun nor hint of sun, though there was not a cloud in the sky. It was a clear day, and yet there seemed an intangible pall over the face of things, a subtle gloom that made the day dark, and that was due to the absence of sun. This fact did not worry the man. 

The gloom that London describes sets the mood for the reader that this story will not likely end well, and the word "pall" is usually used to describe the look of death.  But here, the man is not concerned.  Again, even in the face of obvious signs of adversity and struggle, he simple seems to shrug his shoulders and move on.  It will not bode well for him in the end.