Yeah, Little Miss Sunshine was exactly what I thought of when I saw this. Though, while it is reminiscent of that movie, it's not to the extent that it would alienate someone that didn't know the movie, like they weren't "getting it" or something. (Kind of a pleasant reference for those who do know the movie.)
I like the lines you drew. They look kind of like they contain the shading within themselves, and, while the van is not unrealistically drawn or anything, it doesn't look like it came completely from "our world" - like it's on a different level of "happy" than everything else. Which makes little sense, but it does make me enjoy looking at this van, which must be a good thing.
And I agree with you, about only wanting to drive a VW van. It's absolutely my dream vehicle (although I want to get one and paint it psychedelic myself).
And now I'm thinking of a very similar van that I see everyday on the drive to school. It always drives by, and I always think of Little Miss Sunshine (which is a funny coincidence, because I first saw Little Miss Sunshine at school, in my screenwriting class).