Actors Donovan and Carnie Wilson are the respective children of musicians 'Donovan' and The Beach Boys' singer Brian Wilson, both of whom are heard in the soundtrack. Jason Nesmith, son of ex-Monkee Michael Nesmith, also appears.
In the scene where Katie and her baby are walking through the Haight-Ashbury after she's just quit her job at the strip club, the man she walks by prior to having her purse stolen is clearly supposed to be Charles Manson.
Brian tries to get another man to buy him a beer, saying that he is not old enough to do so. The drinking age in Illinois in 1962 was 18 and Brian would have to be at least that to enlist in the military then.
Playing over the scene with the graphic "Loyola University, 1964" is The Byrds' version of the Bob Dylan song "The Times They Are A-Changin'" which was not recorded until September, 1965. Dylan's version was released in January, 1964.