The dream that Scooby Doo has when he falls asleep in the library is an homage to the TV show, Twin Peaks.
The parents' character design and vehicle of the family at the beginning episode robbed by the Dandy Highwayman is based upon the Clark and Ellen Griswold in National Lampoon's Vacation.
The character of the Dandy Highway and the title of the episode, as well as a few lines of dialog, come from the 1981 Adam Ant song Stand And Deliver.
James Marsters, who voices the Dandy Highwayman portrays an English character but he himself is American, similar to his role as Spike in Buffy The Vampire Slayer.
Amy Akler (Nova) and James Marsters (The Dandy Highwayman) both star in Angel from BTVS universe.