Suggest me a book that is similar to Glendon Swarthout’s “Bless the Beasts and Children”

Bless the Beasts and Children is about a group of disturbed, misfit teens at an Arizona summer camp in the late 1960s or early 70s who escape from the camp and try to rescue a herd of buffalo who are scheduled to be shot.

I would like something similar, with outcast, misfit protagonists trying to overcome their problems and unite to achieve a goal. A gritty 1960s/70s setting would be a plus. I would like it to be written with an adult audience in mind, but the characters should be teens.