Clark tells Rusty (Ethan Embry) and Audry (Marisol Nichols) that he hardly recognizes them anymore, a reference to having a different actor and actress play the Griswold children in each of the four movies.
The living room, in which Wayne Newton and Ellen (Beverly D'Angelo) have dinner, is Wayne's living room from his house in Las Vegas. His house was also on MTV's Cribs (2000), where that same room is featured.
In the original draft for this movie, the Griswolds do not stay at the Mirage Hotel. They stay at the Walley World Hotel and Casino, and Roy Walley was a part of the script. This is a reference to the Griswolds' vacation destination from the first film.
The four vehicles Rusty won throughout the movie, that he and his family drove home at the end were: A 1996 Ford Mustang Convertible, 1996 AM General Hummer, 1996 Ford Aspire, and a 1996 Dodge Viper RT/10.
The Keno scene at the end of the film, takes place at the MGM Grand Hotel Casino. The family is seen entering through the original "lion's head" entrance, which was present when the casino was first built. This entrance has since been remodelled to look like "regular" doors, with a lion statue on top. The Keno section of the casino is no longer there either.
Only Vacation film that does not include a reference to the Walley World amusement park, unless you count the black jack dealer, played by Wallace Shawn, named Marty, as in Marty Moose from the first Vacation (the original film revolved around visiting the park, Clark had a t-shirt for it in European Vacation, and Clark and Eddie drank egg nog from Marty Moose (mascot of the park), and glasses in Christmas Vacation). Wally is also short for Wallace.
The way the Griswolds travel to and from Vegas are a complete opposite from the first movie. In the first one, the Griswolds arrive to their destination by driving and leave by flying. In this film, the Griswolds arrive by flying and leave by driving.
High rollers "Jilly from Philly" (Jerry Weintraub) and his friend with the glasses and dark beard, also appear playing high limit Baccarat in Oceans 11 (2001) with Lyman Zyrga, a.k.a. Saul Bloom (Carl Reiner).
The War dealer is named Nick Mazzola. He was also the Blackjack dealer in Rain Man (1988) at Caesars Palace, as well as a dealer in Casino (1995). In real-life, Nick was a Blackjack dealer at Caesars Palace in the 1970s and 1980s.
RUMOR: First film in the "Vacation" movies to not contain "National Lampoon" in the main title, as John Hughes (writer of the first three films) is no longer the screenwriter, as he was also a writer of the original National Lampoon Magazine.
Although it was Executively Produced by Matty Simmons, it was the only Vacation movie in the franchise (starring Chevy Chase) not to feature "National Lampoon's" in its title. It would take another six years for the Direct-to-DVD spin-off film Christmas Vacation 2: Cousin Eddie's Island Adventure (2003) to be released, and be credited as "National Lampoon's".
One of the guitarists playing on the cover version of "All Along the Watchtower" in the film, is Marc Ferrari. Ferrari was best known for being a guitarist in the 1980s metal band Keel, who scored hits with tracks like "Because the Night" and "The Right to Rock", as well as for playing a Crucial Tault band member in the Wayne's World movies. Ron Keel, vocalist of Ferrari's band Keel, resided in Las Vegas for many years.
Early in development, Chevy Chase had pitched his own idea for a fourth Vacation film, A Swiss Family Griswold, in which the Griswolds are stranded on a desert island. Chase relented when Warner Bros. executive Bill Gerber suggested Las Vegas as the setting, feeling the juxtaposition of the nuclear family in a city driven by sex and gambling would be a more entertaining film.
The radio station broadcast that opens the film gives a radio station ID of k-lite and then plays The Beach Boys. In the Chicagoland area all radio stations call letters begin with a W and not a k. There is an actual radio station in Chicago with the call letters of WLIT and calls itself the light.
This is more a geographical error than trivia. When Audrey is shown standing up in the limo, you can see the Stratosphere tower behind her. That means they are traveling south on Las Vegas Boulevard, but if they had been picked up from the airport, they would be going north, because the airport is south of the city.
The major plot points are foreshadowed in their first limo drive down the strip. Ellen sees a poster for Wayne Newton, a cab with Club Areola, featuring Cousin Vicky, passes by, and a billboard says, "Four cars won already. You could be a winner too."