If the shooting in Alaska and on the Colorado required physical toughness, capturing much of the family history demanded emotional strength. For McCandless's parents and sister, it meant dredging up some old ghosts. The movie includes a violent argument between his mother and father, as well as the father-son tension over careers and money that led, in part, to Chris's decision to leave in the first place.

HILDEBRAND: Sean made a point of getting them to sign off on the script. Carine was involved in writing the voice-over that Jenna Malone reads through much of the movie.

CARINE: If there was something I wasn't comfortable with, Sean was open to my suggestions. He knew how to take our concerns for Chris and make that come through in the film.

POHLAD: As Sean spent more time with the family, I think the story started to open up even more. That caused some controversy. The parents had some ups and downs and nervousness. But Sean handled it all very well.

PENN: There were difficult points. It was tender ground to cross. It was the most treacherous with the parents. We had some serious discussions. Sometimes they were pretty heated. But my first obligation was to Chris. And every time, within a couple of days they would come to an understanding. That takes fucking courage to give in to it like that. And they did it.

WALT: It was hard—harder than each of us thought it would be.

BILLIE: We feel blessed that this was open to us. I thought it was just laid in the cards whether it was going to be a good or bad experience. But we do think it was handled with a lot of respect. We are at peace with what Sean did. Everyone talks about Sean being Hollywood's bad boy. Sean Penn is a gentleman.