I recommend that everyone interested in the history of the Boston Marathon read Tom Derderian's book "Boston
Marathon" "The History of the World's Premier Running Event" issued in 1994.
The first woman to run Boston was Roberta Gibbs who was 126th in 3:21.40 in 1966. (Gibb was 266th in 3:27:17 in 1967.) Gibb was unofficial and was not allowed to have the traditional bowl of beef stew after the race in 1966 She had big headlines and big pictures in the Boston papers that year.
The biggest difference between Gibb and Switzer is that when Gibb applied to run and was turned down she quietly ran anyhow but without entering. She did not wear a number.
Jock was very angry and went after Switzer's number calling her a fraud. When Katherine entered she used her initials and the officials had no idea that she was a female until the saw her on the course.
Those two ladies had completely different personalities and backgrounds. Interestingly, Gibb took a four day bus trip to get to Boston and run. Bobbi Gibb's story is worth reading in addition to that of Katherine. They are both very interesting stories.