Jack Kerouac’s novel of postwar alienation has finally been wrestled onto the screen, with a raft of stars, an indie-lavish $25 million budget, and locations in New Orleans, Mexico, and Argentina. Director Walter Salles (The Motorcycle Diaries) gives this his usual polish, and the two-hour running time allows him to suggest the meandering quality of the novel, which he’s filled out with plenty of sex, drugs, and Beat Generation lore. Predictably, the movie explodes only when Kerouac’s prose provides the voice-over. With Sam Riley, Garrett Hedlund, Kristen Stewart, Kirsten Dunst, Amy Adams, Alice Braga, Elisabeth Moss, and disappointing character turns by Tom Sturridge (whose Allen Ginsberg is no match for James Franco’s in Howl) and Viggo Mortensen (who affects William S. Burroughs but can’t top Kiefer Sutherland in Beat).