The guest actress who plays the waitress Sara Jo in the diner scene was Catherine Bach who famously played another waitress, Daisy Duke on The Dukes of Hazzard (1979) from 1979-1985.
Although they play father and son, Dan Hedaya and Tony Shalhoub are only thirteen years apart in age. However, Jack is said to be 68, two years older than Hedaya actually was at the time of filming, while Adrian is said to be about 47, six years younger than Shalhoub actually was. This would put the characters about 21 years apart in age.
Traylor Howard is obviously pregnant during this episode and hides her bump noticeably with a present when talking to Monk on the phone.
Tony Shalhoub starred on Wings (1990) and Dan Hedaya was a regular guest star on Cheers (1982). While Wings (1990) and Cheers (1982) are not spin-offs, they exist in the same universe. While Wings characters never appeared in Cheers, characters from Cheers visited Wings on several occasions, (mostly) unintentionally either aggravating or being aggravated by the main characters.