I did the AP CS test without being in the class. It only took reading the prep book over (I skipped the practice questions so it was very light reading) and then I studied every day for a bit in the week before the test. Got a 5. That's probably one of the easiest AP courses.
As for calc and physics, I doubt you'll have that much trouble, but my school's calc/physics curriculum is totally different probably so I have no advice.
Really? Wow, the curriculum mustve changed because last time I took it about 2 years ago there was no programming all.
AP Comp Sci has been coding since 1999 at least.
If you need help with AP CS pm me. Java's probably the only language I'm good at.