Tom Sawyer (not Diane Sawyer, Ricky. hehe) is, in both the book and song, the personification of a sort or type of person, the sort of person breaking away from the status quo, exploring and, importantly, the sort who represents both a normative and actual shifting of the human paradigm in the direction of his (man's) rational evolution. This fits, to a greater or lesser extent, with Freud's idea that man evolves in such a way as to shed his dependence on ideals (religion, social norms) and replace that dependence with a greater implementation of reason (leading to self-reliance, a deeper self-awareness and sense of responsibility for ones own "destiny"). Tom Sawyer has thus been a different people at different transitional points in man's evolution (our history). "Todays" Tom Sawyer is exactly what the song says; a leader to the next step in realizing pure reason or rationality; the "space he invades," is his days work, to explore the unknown as progress towards truth; the "friction of the day," is the resistance he faces from both people's unwillingness to embrace change as well as the intellectual rigor of tackling what hasn't already been explored (the guy who cuts a path through the forest faces resistance from the brush leaving those who follow behind with little to do but be complacent and stagnate). He (TS) does all of this with a mind filled only by his own conclusions (i.e. "not for rent"), and via the power coming from honest intellectual reciprocity or dialectical process ("he gets high on you," "he gets by on you"). As far as "riding out the days events," the song is referring to fate controlling what life gives to us, even though it is our responsibility (and can be a point of pride if done well) to live our own life with what fate hands us. In RUSH's "Roll the Bones," Peart refers to the same notion, "we draw our own designs, but fortune has to make that frame."