how is the text influenced by having the story told through Huck, an unschooled, mischievous, twelve-year old boy?

Huck is, first of all, completely uninhibited. He just tells it like he sees it based on his past experiences. He is influenced by his experience with his father, the drunken Pap, with the Widow Douglas who tries to civilize him, and his need for survival and "fun." He has the ability of a child to be open to new experiences, and he certainly is open to being friends with Jim since he understands inherently that Jim is as good a man as he has ever met and race has nothing to do with his goodness or badness.