Dave Eggers has a pretty good reputation among this generation of writers, based in part on his funny if overlong (and audaciously titled) "A Heartbreaking Work of Staggering Genius." His wife is also a writer, Vendela Vida, author of three books including another well-titled tome, "Let the Northern Lights Erase Your Name." Together, they've collaborated on the story for the new Sam Mendes film playing at the Rialto Lakeside, more succinctly titled "Away We Go."

They are all doubtless talented, Eggers and Vida and Mendes. The film they've created is full of fine performances as well, from a supporting cast that includes Allison Janney, Jeff Daniels, Catherine O'Hara and Maggie Gyllenhaal among others. And the two leads are portrayed by Josh Krasinski and Maya Rudolph, he of television's "The Office" and she - well, it hardly matters what else she's done (though we'll get to that in a minute). Maya Rudolph is the main reason to see this movie, and it's reason enough.

"Away We Go" is essentially a road movie, about a young "f***ed-up" couple, Burt and Verona, who live in a beat up shack in Colorado with a cardboard window and faulty wiring. When she becomes pregnant they begin to wonder, somewhat belatedly (six months in), where they're going to raise their child. So they visit first one distant relative then another, one distant friend and a closer one, looking for the right fit. Where will it be? Phoenix or Tucson? Montreal or Miami?

The road movie is a staple in American cinema, and when paired with young love it sometimes turns savage ("Bonnie and Clyde" comes to mind, or "Sugarland"). The only savagery here, fortunately, is an embarrassment of bad behavior by their friends. If you've seen the previews you've seen the highlights - Janney's a holy terror of outrageous remarks, Gyllenhaal a self-righteous kook, O'Hara and Daniels smug and uncaring parents.

There are two things that came to mind in watching this film. Point One, what a slew of self-absorbed characters this is. The people Burt and Verona encounter on their odyssey are caricatures - they are almost entirely the manifestation of whatever cliché gave them birth. And the many scenes that show our young couple's encounters with them turn into exercises in buffoonery.

Which is not to say the movie is without laughs, or pleasures - Janney is a crack-up, putting the uptight press secretary of "West Wing" leagues behind her. (Jim Gaffigan as her long-suffering and slightly paranoid husband is great, too.) But the film is less a movie than a comic book - Mad Magazine, in fact. It has that juvenile disdain for grown-ups which that cult rag does, or did - perfect for the sub-adolescent, but somewhat tiresome in the long run. (Running time: 97 minutes.)

It reminded me less of any Mendes films - "Revolutionary Road" or "American Beauty" - than it did "American Splendor," about oddball cartoonist Harvey Pekar. It even looks like a cartoon, somehow (and its press ads are drawings, not photographs) with its crayola colors and buffoonish characters. (Eggers is a former comic book artist, inking something called "Smarter Feller" at some point.)

Okay, now Point Two. The biggest question I had is, what does Verona see in Burt? With that smeary beard of his, Krasinski is a completely unconvincing insurance salesman, despite his Casey Kasem imitations on the phone. (This isn't a spoiler, it's in the first five minutes.) Okay, so he loves her: but is that really enough? He struck me not as charming, but perhaps only slightly less goofy than, well, Goofy. Gangling, uncoordinated, socially incoherent, deliriously innocent. And he's never, ever without his black-rimmed glasses - well, perhaps in the very first scene, but we don't see his face. (Now that's a spoiler.)

Then there's that single reason to see the movie I mentioned. Maya Rudolph is the solid core of this movie, and her presence infusing the film with dignity and purpose beyond its due. She's got Earth Mother down pat, but it's not a formulaic portrayal, but complex and moving. She is luminous, at once the center of the universe and a lightly comic presence. No wonder it's a road movie: anybody would be a fool not to go to the ends of the earth for her.

I only remember seeing Rudolph once before -- I don't usually "Saturday Night Live," not since Belushi died, but I understand she's a regular. In the ill-fated Mike Judge film "Idiocracy" she played the other time traveler - Luke Wilson is the first - an average woman sent 500 years in the future. She seemed out-of-place as an inner-city streetwalker, really, even more than the role suggested. And aside from a few reaction shots she failed to make much of an impression beyond the physical. (Can't fault streetwalkers for wardrobe.)

The theme of "Idiocracy" was that while the smartest among us keep putting off having children until they're ready, and then only have one or two, the rest of the human race will just keep pumping out brats as fast as biology allows. Eventually the species will become overwhelmed by stupidity, so dumbed down that today's average guy will be a genius a few centuries hence. (A profound philosophical observation from the creator of "Beavis and Butt-head," I know.)

The funny thing is, this argument is made almost verbatim about two-thirds of the way through "Away We Go." One of Burt's college friends (nice turn from Chris Messina, the stoner son from "Humboldt County") observes that his mid-30s wife has had 5 miscarriages. They've waited too long to have children, while "a million 14-year olds get pregnant every year."

I guess what this all means is that "Away We Go" finds its inspiration in strange places - 50s comic books, road movies, Mike Judge, and the ballads of Alexi Murdoch (soundtrack album available from Amazon).

Maybe the disappointment of "Away We Go" is realizing our reduced expectations from the next generation of artists, the crème of the literary thirty-somethings, as much as the reduced expectations our young couple faces. At the end of the movie, they are somehow taken care of, finding their way Home as if by magic. Or contrivance.