Maude Frickert is actually a character that Jonathan Winters developed for comedy albums, so he voiced both himself and her.
First time Velma says, "Jinkies," which was ad-libbed by Nicole Jaffe. Shaggy had uttered a similar expression in The Dynamic Scooby-Doo Affair (1972).
Maude Frickert says Fred looks like her hero, country singer and actor Glen Campbell. This is a plug for The Glen Campbell Goodtime Hour (1969), also produced by CBS.
Jonathan Winters is the first of many celebrities who played themselves in the Scooby-Doo franchise.
Jonathan Winters was also at cross-purposes with a scarecrow in The Land of Oz (1960), where Winters' General Nikidik was the enemy of the brainy Scarecrow of Oz.