The Black List script that got Nat Faxon and Jim Rash noticed, earning them the gig co-writing “The Descendants,” makes for an endearingly sweet coming-of-ager, now that the ex-Groundlings have taken matters into their own hands and made “The Way, Way Back” themselves. The story of a teen desperate for a father figure who finds encouragement from a wild-and-crazy water-park employee — rather than from the guy auditioning to be his stepdad — can be explosively funny in parts, but overall feels pretty familiar, relying more on its cast than the material to win favor. Distribs will scramble for this eminently marketable debut.

Named for the outward-facing bench in the back of an old station wagon, the pic identifies with the character stuck in that seat, 14-year-old Duncan (Liam James). The kid is sleeping en route to his summer vacation when Trent (Steve Carell), the new guy his mom (Toni Collette) is dating, puts the question to him: On a scale of 10, how would he rate himself? Confused, Duncan fumbles a half-hearted “6,” only to have Trent correct him: No, he’s really more of a “3.”

That exact exchange, which Rash says originated with his own stepfather years ago, left scar tissue deep enough to inspire the script. However, Carell’s such a likable actor, while James so aptly embodies a sheepish kid with no special skills, the effect isn’t quite the same onscreen. Still, it’s not the sort of thing one says to a kid, and the film ultimately becomes the story of how Duncan finds the self-confidence to improve his score — but only after the adolescent dullard manages to emerge from the shadow of the other characters, the rest of whom are written as irrepressibly hilarious cut-ups. (Allison Janney in particular threatens to steal the show as the filter-less lush who lives next door.)

Lucky for Duncan, he makes a connection the moment the station wagon rolls into town, spotting Owen (Sam Rockwell) in the car behind them. It’s a weird scene, especially considering Rockwell’s unkempt and slightly pervy look — like a meet-cute between a child molester and his future prey — though the movie’s more innocent-minded than that (blue humor and language could earn it an R rating, but the pic cares precious little about so-called “adult situations”).

The way Nick sees it, Owen has the coolest job any 14-year-old could imagine, working at the nearby Water Wizz amusement park, and he soon starts sneaking off on his bike to hang out. Owen seems to understand precisely what the shy boy needs, giving him a job and gradually drawing him out of his shell. Here, the two actor-scribes join longtime friend Maya Rudolph as eccentric Water Wizz employees, and though much of their kidding is lost on the humorless Duncan, teaching the kid to smile seems to be victory enough.

Duncan keeps his new job a secret, not even telling the first kissable girl-next-door (AnnaSophia Robb) where he disappears each day, while mom and Trent are too busy partying with friends (Rob Corddry and Amanda Peet) to worry about Duncan’s whereabouts. It’s all a bit too sitcomish to sound sincere, as when sister-to-be Steph (Zoe Levin) takes one look at Duncan grinding with her dad’s latest fling and quips, “Enjoy therapy.”

The fact that Rash survived to co-write this script suggests things will work out for Duncan, though the scenes of his progress — especially a completely out-of-character breakdancing number that earns him the nickname “Pop ‘N’ Lock” — aren’t nearly as entertaining as the inappropriate grown-up behavior he’s running away from at home.

Besides, moviegoers have seen nearly all this on-the-job stuff before, whether in Greg Mottola’s similarly autobiographical “Adventureland” or in corny ’80s movies that take place when this story clearly ought to. Going the period route probably would have cost too much, but it would have helped to explain the film’s retro music choices, as well as the fact that Trent still drives a classic station wagon.

In terms of production value, “The Way, Way Back” looks great as it is, reminiscent of the similarly sweet-and-sour “Little Miss Sunshine” (on which Carell and Collette previously collaborated), though that film certainly made more of its signature vehicle.

The Way, Way Back

  • Production: A Sycamore Pictures, DoubleYou, OddLot Entertainment production in association with What Just Happened Prods. (International sales: WME/CAA, Los Angeles.) Produced by Kevin J. Walsh, Tom Rice. Executive producers, Nat Faxon, Jim Rash, Ben Nearn, Gigi Pritzker, George Parra. Co-producer, Rebecca Rivo. Directed, written by Nat Faxon, Jim Rash.
  • Crew: Camera (color), John Bailey; editor, Tatiana S. Riegel; music, Rob Simonsen; music supervisor, Linda Cohen; production designer, Mark Ricker; art director, Jeremy Woodward; set decorator, Rena Deangelo; costume designers, Ann Roth, Michelle Matland; sound (Dolby Digital), Kevin Parker; supervising sound designer, Scott Sanders; supervising sound editor, Perry Robertson; re-recording mixer, Patrick Cyccone; special effects supervisor, Christopher Walsh; visual effects supervisor, Sean Devereaux; visual effects, Zero VFX; stunt coordinator, Paul Marini; assistant director, Ramses Del Hierro; casting, Allison Jones. Reviewed at Sundance Film Festival (Premieres), Jan. 21, 2013. Running time: 102 MIN.
  • With: Trent - Steve Carell<br> Pam - Toni Collette<br> Betty - Allison Janney<br> Susanna - AnnaSophia Robb<br> Owen - Sam Rockwell<br> Caitlin - Maya Rudolph<br> Duncan - Liam James<br> Kip - Rob Corddry<br> Joan - Amanda Peet<br> Peter - River Alexander<br> Steph - Zoe Levin<br> Roddy - Nat Faxon<br> Lewis - Jim Rash<br> Neil - Adam Riegler