The directions the receptionist gives the Griswolds to their rooms are accurate for the Mirage Casino.
The living room in which Wayne Newton and Ellen have dinner is at Wayne's real-life Las Vegas home. When his house was on MTV's Cribs (2000), the same room was featured.
Clark tells Rusty and Audrey that he hardly recognizes them anymore. This is a reference to the fact that different actors and actresses have played the Griswold kids in each of the "Vacation" movies.
The Griswold's home is the same house featured in Férias Frustradas de Natal (1989). When Clark pulls into the driveway, you can see the neighbor's house still has the same second floor window, the one Clark had ruined when hanging Christmas lights.
Christie Brinkley: As the Girl in the Ferrari, the role she reprises from Férias Frustradas (1983). The Nevada license plates on her red Ferrari convertible read, "MAMA," alluding to the fact that she become a mother.
Steve Wynn: As a floor supervisor in the blackjack pit in Clark's first encounter with Marty the Dealer. Wynn was the original developer and owner of The Mirage.
Toby Huss: As the Frank Sinatra-impersonating fake I.D. salesman. Huss also impersonated Sinatra in Por Água Abaixo (1996) the year before this film's release, and eventually incorporated his imitation and strong resemblance of the crooner into his alter ego character Rudy Casoni.