Here’s about half of a funny movie. The funny parts mostly are physical comedy. The not-so-funny ones are where Robin Williams seems to be improvising. His routines were funny for about a decade, but now they’re getting tiresome. And this movie has to contend with a big obstacle as soon as they crank up the engine of that big ol’ RV: National Lampoon’s Vacation. That remains the quintessential family road movie, though }}Little Miss Sunshine}} is as good, in a different way. Clark Griswold and family endured as many horrors as Robin and family here, and yet Chevy Chase managed to create a unique character. No matter what happened, Clark rose about it with maniacal good cheer and optimism, and there was always the touch of the devil in him that made it all even funnier. Robin Williams’ character here is strictly off the shelf. You know the story without me even having to tell you. Husband is trying to succeed at work and family feels neglected. They pile into the RV (don’t ask why), sniping at each other and at Dad, and soon find themselves transformed into a loving family again. (I’ll give them points for a scene where Robin asks his daughter where she wants to go to college. Stanford? How the hell do you think I’m gonna pay for that, you privileged little bitch? By working, that’s how, something you have no experience of.) The first part of the movie is much like taking a cross-country trip in close quarters with people you hate; I’d sooner be on a Greyhound Bus. But then the “rednecks from hell” show up … at least that’s what they’re supposed to be, at first, before we discover they’re really just the finest, most genuine down-to-earth shitkickers you’d ever want to meet, aw, shucks! Thing is, from the git-go I liked them better than the Williams family. They’re played very well by Jeff Daniels and Kristin Chenoweth, who you may remember from “The West Wing,” and who turns out to be a world-class operatic soprano, as we saw in Leonard Bernstein’s Candide not too long ago. Who knew? They are the brightest lights in a rather murky mixed comedic bag. I also have to mention that the daughter is played by Joanna “JoJo” Levesque, who looks like Lindsay Lohan’s little sister, and she can sing!