Sam Mendes loves women. Or rather, he gives actresses lots of screen time and seems especially fascinated by louder-than-life mothers who overestimate their own charm and/or intelligence. Both American Beauty and Revolutionary Road feature a brittle bitch mom. His romantic comedy Away We Go serves up two.

The title, as it happens, sums up the script and performances. Respectively cast as Lily, a bipolar redneck, and LN, a New Age control freak college professor, the wonderful Allison Janney and Maggie Gyllenhaal get to sail way, way over the top.

Either or both women may earn an Oscar nomination (the Oscar voters love this kind of thing) but I should point out that they are supporting players. The hero and heroine of the movie are a thirtysomething couple, played by less familiar faces. Burt (John Krasinski) and Verona (Maya Rudolph) are about to have a baby and suddenly find themselves untethered to any particular place. They begin a road trip across America in search of “home”.

Krasinski and Rudolph are refreshingly normal-looking actors who deliver the film’s many excellent lines with aplomb. Novelist husband and wife team Dave Eggers and Vendela Vida have picked a nice genre for their scriptwriting debut and, à la Meet the Parents, their story is especially good at pointing out the foibles of baby boomers.

The scenes involving Burt’s parents — out of the blue, they announce they are moving to Belgium — are hilarious. Burt and Verona are furious, the old timers giddy as teens. The laughs feel earned, because we can see both points of view.
When it comes to the rest of the couple’s family and friends, though, we are largely invited to sneer. The odds are especially stacked against Gyllenhaal’s college professor. She constantly patronises Verona, who is mixed race (“Your people have such a great oral tradition”). True, there are plenty of racist liberals, but would
they expose themselves in this way?

Instead of putting effort into showing us LN’s prejudice, Eggers and Vida just make her look like an idiot, so we can all go: “Phew, I’d never say anything as idiotic as that, I must be racism free!”

Some of the interludes touch on important subjects, miscarriage in particular, but in the time allowed, the conclusions reached seem glib, not to mention conservative. (If you are a thirtysomething woman who is having trouble conceiving, do NOT go and see this movie.)

The more the film insists that we see Verona and Burt as perfect, the more smug and unreal they appear. The messy mix of twee maundering and frat-boy slapstick might work if one thing were added: a caption at the end that read: “... and then Burt woke up”.

Fantasies fuel cinema, but Mendes’s much vaunted imagination seems all played out.