Joe Silver appears here only in voice, a talent he often employed in his acting career. His voice, in fact, appears over the phone twice in the role of two different characters: the friendly Ted Bower of Seattle, WA, and the gruff brother-in-law of candidate Clark Williams. He does appear as a character in an earlier episode as Coach Edwards in Patty, the Pioneer (1964).
Mr. Duffy boasts that singing voices of Tony Bennett, Frank Sinatra, and Barbara Strysland, by which he means Barbra Streisand, are used on the campaigns sound truck.
'Hustings' comes from 'husthings', an Old Norse word meaning 'house assembly', which was a gathering for making decisions concerning the realm or manor of a lord. English adopted the term to mean any meeting and eventually came to mean literally a dais for political speeches, hence Martin and Patty's comments about mounting the hustings.
This is the fifth of eight credited appearances Timothy Neufeld makes in the series, sometimes as Tim, sometimes as Tom, other times an unnamed character, and, of course, as here playing John.