As having served in the role of producer for many episodes, it's a chance for Henry Winkler to make an appearance as Wilton Newberry, the uncredited role of the Attorney for Harry's will.
Marion Ramsey from Police Academy (1984) makes a guest appearance at 13:49, dressed as a police officer.
Henry Winkler and Marion Ross of Happy Days (1974) fame both make guest appearances. Winkler plays the attorney while Ross plays Sister Robin.
Wendy O. Williams guest stars as Big Mama. Williams was the lead singer of the infamous punk band The Plasmatics, a stripper and starred in adult films. She attempted suicide two times before her final, sadly successful, attempt in 1998.
The classic car is a Nomad. Guest star James Doohan's Star Trek (1966) character "Scotty" was killed (and resurrected) by a machine named "Nomad" in The Changeling (1967).