Claudia Stone, played by Karen Black, refers to herself as "a 19 year old girl". Black was 28 at the time.
After being wounded in the leg by a ricochet bullet, Bob Torin (Anthony Eisley) jokingly tells David (Roy Thinnes) he went through Anzio without a scratch. He is referring to The Battle of Anzio, a battle of the Italian Campaign of World War II that took place from January 22, 1944 (beginning with the Allied amphibious landing known as Operation Shingle) to June 5, 1944 (ending with the capture of Rome). The operation was opposed by German forces in the area of Anzio and Nettuno. Anthony Eisley actually did serve in the United States Navy during World War II.
At the beginning of the episode a sign says they are entering "Harper County, Vermont" and the population is 7,162. Vermont has fourteen counties, but none named Harper.
Cyrus Stone (Laurence Naismith) says he is 71-years-old, however Naismith himself was only 59-years-old (but only two days short of his sixtieth biryhday).