I think that you might need to give us more information if you want to get useful feedback.
It was a long time ago but I went to a high school that did not offer any AP classes. I still got accepted to MIT. Universities do not expect you to fix your high school. The top ranked universities do expect you to excel at whatever high school you attend.
In terms of extracurricular activities, they do not need to be through your high school. A job is an extracurricular activity. Something that you do at the YMCA could be an extracurricular activity. Organizing neighborhood kids to clean up a park could be an extracurricular activity.
Dartmouth College and Harvard do expect students to show the ability to excel at whatever they do. They also expect students to write clearly in whatever is written to go along with their applications.