The Incredible Adventure of Jojo (and His Annoying Little Sister Avila)

How's a boy suppose to be a man with his sister always on his back?

A mother takes her two young children to go visit grandma out in the woods. On the way back, the mother gets into a car accident, and the two children are forced to make it back to grandma's on their own, encountering hobos, wolves, and raging rivers along the way.