In The Lucky Ones, a trio of U.S. soldiers who have just returned from Iraq — Tim Robbins as a 40ish veteran, and Rachel McAdams and Michael Peña as younger grunts on a 30-day leave — team up to drive across the country. The last time the Iraq war was the impetus for a road movie, with John Cusack gawking in his aviator frames in Grace Is Gone, I broke down and cried (not from the tragedy, from the film’s excruciating ineptitude and tedium). The Lucky Ones, though, isn’t a meandering, didactic downer. The word ”Iraq” is never mentioned, and the film has been designed as a kind of triple buddy flick, done with enough comedy and ”pace” to fill out half a season of a TV series. That’s what’s likable about it — and also what’s suspect. Each character is defined by one issue of extreme gravitas that is treated as a situation, an arc to be tidily resolved. Robbins learns that his wife wants to leave him (a credible problem staged in an overdone way), and he must find $20,000 so his son can attend Stanford. McAdams, who claims no kin, wants to join the family of the soldier who saved her. And Peña has a thigh wound that’s turned him impotent. It’s all very facile — war’s domestic fallout made into feel-good fodder — but The Lucky Ones isn’t dull, and the actors do quite nicely, especially McAdams, who’s feisty, gorgeous, and as mercurial as a mood ring. B?