Excellent determination to meet your personal goals! I've looked through the ap art, and it's quite interesting.
A careful read of this document makes me think that you could set this up as a mentor ship with an art-knowledgeable teacher (not as a full-one "on the books" course). The content is entirely up to you, I think, then in a collaborative way, meeting up with the mentor/teachers to assess the portfolio content to see if it meets the ap art criteria. There is actually a line in the document about ap art being in some cases "self-directed", and also "home schooled" - and that ap art is an evaluation process, not a skill/craft teaching process.
The self-determination to do this is a measure of the self-determination of a successful artist. Good luck!
There is very high-quality, and free on-line material out there for some of the art skills, as well.
Not a full-on specific answer, but I think you can do it. I did this for all my high school courses for one year back in the day. Entirely on my own, just met with a teacher once a week to check in how I was doing. It's not for everybody, but the alternative education model worked for me and a bunch of other determined, self-directed kids who were otherwise at that time board stiff in class. Not quite the same as your art adventure... but... shows what a determined and disciplined high school student can achieve.