Into the Wild succeeds in spite of itself. Sean Penn’s adaptation of the Jon Krakauer best-seller falls into an almost inevitable trap. It tells the story of the doomed eccentric Christopher McCandless, who cut off all contact with his family right after graduating from college to explore the West without money, a car, or other material possessions, adopting the name Alexander Supertramp, and eventually setting off alone into the Alaskan wilderness.

The trap is that Penn, and by extension the audience, buys into Chris’s dream too unquestioningly. There is little or no distance or irony. What Chris does in the film could be described as selfish, reckless, and foolish, although he is a visionary of sorts. But as portrayed by the gifted young actor Emile Hirsch, and as seen and heard through Penn’s camera and script, Chris is utterly charming, beloved by nearly everyone he meets, and ever true to his dream – virtually a saint. (He’s even celibate, sweetly turning down the sexual advances of a teenage girl he befriends.)

But even though the film would be much stronger if it took an edgier and less rose-tinted stance toward Chris’s adventures, the story itself has a powerful pull, gravitational, magnetic, almost magical. It becomes a classic road movie, with an irresistible hippie-environmentalist twist. Though you may know it’s going to end sadly, the journey itself is often exhilarating. In fact, the film seems to be suffering commercially because potential viewers don’t want to go watch a young man die. But while the film is emotional, the emotions are overwhelmingly weighted toward joy rather than sorrow, as you might expect from Penn’s infatuation with Chris and his story.

The entire cast is excellent. Hirsch is in nearly every scene of a 140-minute film, and rarely if ever hits a false note. His likability and spirit carry the film (even as they push it away from the harder edge of art). Catherine Keener, Brian Dierker (whose first film as an actor this is) and Vince Vaughn are all very fine as people whose paths cross with Saint Supertramp in his travels. And Hal Holbrook has one of the greatest roles of his career, giving one of the year’s best (and, surprisingly from Holbrook, least actorish) performances as an aging widower who is the last person to speak to Chris before his final journey. (The Keener and Holbrook characters are the only ones who try to tell Chris directly that what’s he’s doing is hurtful to his family and potentially dangerous to himself. Not surprisingly, their scenes are the most emotionally resonant in the film.)

The first-rate photography by Eric Gautier (The Motorcycle Diaries, Kings and Queen) captures the beauty and excitement of Chris’s travels without falling into nature movie clichés. The Eddie Vedder songs that fill the soundtrack are not my cup of tea, but they blend in with the movie’s ambience and don’t become a distraction. The film is a bit grandiose and overlong, with superfluous prologues and asides and portentous bits of dialogue, but these qualities are all part of Penn’s conception. He has made the movie he wanted to make. And in this case it may be better to enjoy it for what it is rather than complain about what it’s not.