Some of my favorite movies as a child were the National Lampoon's Vacation films. Back when Chevy Case was funny and National Lampoon was creative, they did a series of films that started a trend of trip disaster movies, like RV and Little Miss Sunshine. The Hollywood Reporter has some details about the plot, and they are actually pretty exciting:
The story focuses on Rusty Griswold, the son of Clark Griswold, the protagonist of the initial movies and portrayed by Chevy Chase. The younger Griswold is now a father in his own right and takes his family on a road trip vacation.
Hit the break for the rest of the quote.
The characters would acknowledge that first trip (from the 1983 original film,) making the movie more of a sequel than a reboot. Chase and Beverly D'Angelo, who played the mom in the original movies, will have room to make appearances as grandparents, providing a sense of continuity, though no deals are in place.
My personal hopes for the film are that it will retain the feel of the original films, while adding in some of the newer comedy styles of films like Little Miss Sunshine. My one real request is that you keep Chevy Chase out of the film. He was funny 15 years ago, but not anymore. It would make for better continuity, but not a better film.