It’s impossible to separate my feelings about the film “On the Road” from my feelings for its source Jack Kerouac novel. Adults don’t typically run around espousing their love of the book as often as teenagers and young adults do, and it has been years since I’ve proudly waved the paperback around as a badge of initiation into the world of required cool reading.

Director Walter Salles again delves into the world of photogenic male road trippers that he also explored so beautifully in his 2004 Che Guevara biopic “The Motorcycle Diaries.” Both that and “On the Road” evoke the rambling, unstructured worlds of their protagonists as they get behind their respective wheels and simply go, and sometimes rambling is another word for “boring” or “repetitive.”

However, if you don’t like the film “On the Road,” I don’t think it’s Salles fault; I found the adaptation to be extremely faithful, and if anything, it was its faithfulness to the source that occasionally hurt it. Reading and watching simply aren’t the same thing.

So, can it be argued that the main characters, Dean Moriarity and Sal Paradise, are self-involved, naïve, and self-indulgent? Most definitely. It’s hard to see them as heroes, but plenty of people do. I thought it was interesting to witness my own reaction to their antics now that I’m older. This time around, I mostly worried about their various cast-off progeny, and don’t even get me started about William S. Burroughs’ poor kids.

The success of the film rests on the shoulders of the male protagonists, Dean and Sal. The story is only about Sal’s life as he experiences it with Dean. Fortunately, two relatively unknown guys played them. I was initially worried about Dean, whose irresistible charisma basically drives everything that happens in the story, which is basically sex, but Garrett Hedlund won me over. Maybe he was a little too clean cut, but his performance was good.

Hedlund especially gave Moriarity a sense of conflict about his actions, one which he rarely acted upon. Still, you could tell he felt bad about some of the crazy stuff he was doing. The movie simplifies him a bit, and reduces some of the creative urges he exhibits in the novel until primarily the carnal ones remain. Nevertheless, the oft-nude Hedlund is convincing as a guy who shakes up almost everyone he meets.

Meanwhile, Sal Paradise, the name Kerouac gave himself, is our narrator, and British actor Sam Riley was also affecting. He was appropriately reticent, hanging back, observing, and writing it all down. If you found their dialogue to be too poetic, and their drive to “live” to be too dreamy — dare we say, immature? — then you’re missing the point. Even Sal Paradise has moved on by the end, and this distance enables him to tape together that roll of paper and start his novel.

The female roles were all filled by more famous actresses, and Kristin Stewart reminded me of why I liked her in the first place, in movies like “Into the Wild.” Quiet and natural is more her thing, and she was seductive and believable and also oft-nude here. Kirsten Dunst was more grown up than I have ever seen her as the woman unlucky enough to bear Dean Moriarty two children, and her scenes, in which she scornfully calls Dean out for behaviors which she no longer finds exciting or free, are some of the films’ most resonant.

And, for pure author impersonations, I am hard pressed to choose between Viggo Mortensen as William S. Burroughs or Tom Sturridge as Allen Ginsberg, or as he’s named in the novel “Carlo Marx.” Both of their screen time is so limited compared to the two leads, so maybe it was just that I didn’t have time to grow weary of them, but they energized their surroundings every time.

It is tempting to try place the film in context with its history as a book, or the real people and events that inspired the book, or with your own experiences, but I think it’s best to simply let this movie happen and see how you feel. Nothing will ever affect me the way reading that book when I did affected me, but this was a film experience that can stand on its own as an achievement, even if that is not possible.