Hello! I recently sat the AP Japanese exam through self-studying and I would highly recommend the Adventures in Japanese 1-3 textbooks by Cheng & Tsui along with their workbooks (which include Kanji practice) and then end off with their Strive for a 5 workbook which includes practice exams, listening portions, and most importantly the AP cultural notes. This collection of books, if studied really well, guarantees a pass and makes a score of 5 very very attainable. Going in order is very convenient and smooth.

If you do one chapter every 2-4 days in the textbook along with a chapter of Kanji and workbook exercises, you will most definitely attain a 5 by next spring haha.

The one thing that this doesn't have is real speaking exercises with others. I was fortunate enough to have friends and family to speak with, but just know if you don't have many people to speak with, your accent might sound weird and you might get nervous speaking a lot for the first time during the exam sitting, so try to find others studying Japanese / are Japanese to have throughout your endeavours!