RV isn’t a movie in which every joke connects with every audience member, and yet, to be honest, it isn’t a movie in which that needs to happen. A sort of pureed mélange of National Lampoon’s Vacation and a half-dozen other familial road movies, it sacrifices sensible story progression for broad slapstick at times (an attempt to pander to those who can’t get enough big screen laughs at spewed sewage), yet it’s so pleasantly cast and still locates, however awkwardly, genuine feeling on a consistent enough basis to easily qualify as a passably worthy family film.

Robin Williams stars as Bob Munro, an overworked executive at a soda company. Bob and his wife, Jamie (Cheryl Hines), have big plans for a Hawaiian vacation with their daughter Cassie, (Jojo Levesque), locked in the throes of teenage petulance, and 12-year-old son, Carl (Zathura‘s Josh Hutcherson), who hides an insecurity about his short stature behind gangsta-culture posturing and a budding regimen of iron-pumping. As a generally loving but increasingly fractious family driven by their own separate agendas and interests, this will be the one opportunity all summer for them to spend time together.

Tapped by his unreasonable boss (Will Arnett), though, Bob finds himself having to step in at the last moment and help broker an impending business deal in order to safeguard his job. Ergo, he secretly cancels the Hawaii trip and loads his family up in a garish, rented recreational vehicle for a drive to the Colorado Rockies, all while concealing his ulterior agenda: to do the necessary prep work leading up to his big meeting on the outskirts of Denver.

Directed by Barry Sonnenfeld — who looms over the picture, literally, as the otherwise unseen RV salesman, painted on the side of the camper with outstretched arms and a goofy grin — RV naturally features Williams in his trademark manic nice guy mode, and accordingly there’ s the attendant ad-libbed lines of dialogue as Bob tries to spin various situations to his advantage. (“We’ll do Hawaii for Christmas,” he says at one point. “C’mon, it’ll be you and me and a bunch of elderly Jewish people — we’ll have the ham all to ourselves.”)

Eschewing the opportunity for serial wacky cameos, RV instead latches on to a sunny, wide-eyed family of full-time RV-ers fronted by Travis and Mary Jo Gornicke (Jeff Daniels and Kristin Chenoweth, respectively), and attempts to mine comedy from the Munros’ increasingly uncomfortable interactions with them. This is done with varying degrees of success, for while Daniels and Chenoweth are game, the improbability factor with regards to the Gornickes’ sustained obliviousness weighs down a few scenes.

Where the movie succeeds, though, is in its casting and the manner in which it aptly locates the exasperation of all parties involved. Hines is a perfect counterbalance to Williams, and Levesque and Hutcherson deliver solid performances in what could easily be cardboard characterizations in the hands of a less specific director than Sonnenfeld. Also, too often in family films there’s a singular point of view impressed upon all the characters, but RV showcases an admirable willingness to indulge in frank, if broad, disagreements. You get a sense of why Bob feels pressured (to provide for his family), but also see everyone else’s frustration.

Now, are there scenes we’ve visited before? Yes. And are they drastically and creatively re-imagined herein? No, not always. In the end, too, after the secret of Bob’s meeting comes out, a moralistic ending gives way to a cast karaoke version of “(Get Your Kicks on) Route 66,” a la the Farrelly brothers’ effusive end-credit celebrations. If this and a few other moments feel like prescribed hitching posts along RV‘s trail, you’ll likely shrug it off, and won’t mind too much given the satisfaction the movie engenders with a broad cross-section of your own family. It’s aided by a copious slate of DVD extras, kick-started by a telestrator commentary with Sonnenfeld, five making-of featurettes, storyboard-to-film comparisons, a solid gag reel and an alternate scene. C+ (Movie) B+ (Disc)