No idea about title or author... It's a book I read when I was a kid (preteen?). It's about a teenaged girl (Marcy, maybe?) whose family lives in an apartment in New York City. They are close friends with a family that has a geeky teen boy (Joel) a year older than the girl. She doesn't like him, thinks he's weird, and of course the two sets of parents who are such great friends decide to ditch the rat race and "go back to the land" together on the same homestead. So the book is all about how the girl adjusts to this extreme change in lifestyle, from shopping whenever she wants for clothes to having to make her own b/c there's no money to buy clothes (and no place to buy them anyway, since they live out in the middle of nowhere and even the school bus doesn't come by their road). Everyone works the farm and they do everything for themselves.
Is this even remotely familiar to anyone here?