I want to know the main topics and understandings that would be covered in an AP class because my school doesn't provide one.
Are you going to try to take the AP test or are you just trying to improve yourself/general college readiness?
Birdsall Viault's Modern European History. It's informative without being overwhelming and I'm conviced this helped me get a 4... in 2006. But this plus 5 Steps to a 5 should be good.