Self Studying for APs

Hey guys! I was looking to clear up some space in my schedule by self studying for some AP tests, but with other difficult classes, I don’t want to overwork myself. Based on your knowledge and experiences, which AP classes are easy to self study for, and what books and/or resources would you use? Thanks in advance.

Human Geography, Psychology, and Environmental Science cover one semester each (not a full year) and are pretty easy to self-study. The Princeton Review books tend to be the most concise for self-study.

Thank you!

Bump

AP Psych and AP Bio can both be self studied fairly easily.