What was McCandless like as a child and as a teen?

As a boy, Chris was precocious.....

At the age of two, he got up in the middle of the night, found his way outside without waking his parents, and entered a house down the street to plunder a neighbor’s candy drawer.

He was extremely intelligent:

In the third grade, after receiving a high score on a standardized achievement test, Chris was placed in an accelerated program for gifted students. “He wasn’t happy about it,” Billie remembers, “because it meant he had to do extra schoolwork. So he spent a week trying to get himself out of the program. This little boy attempted to convince the teacher, the principal—anybody who would listen—that the test results were in error, that he really didn’t belong there.

Chris enjoyed being alone.

“Even when we were little,” says Carine, who was born three years after Chris, “he was very to himself. He wasn’t antisocial— he always had friends, and everybody liked him—but he could go off and entertain himself for hours. He didn’t seem to need toys or friends. He could be alone without being lonely.”