I'm taking A&P (offered as separate classes) through UC Berkeley extension. They offer both in person and online sections, and I picked online because I wanted the flexibility to be able to work, go to interviews, move at a faster pace, etc. I've also taken in person classes from them and had good experiences for the most part. Each class is about $800.
For the online classes you can enroll any time. They are broken down into units. Each course has 8 units, and each unit is between 2-4 chapters out of the book. You could sit down and plow through the whole course in a couple weeks, but they won't let you submit more than one assignment per week, so you have to at least space that out. Also, you need to wait 3 months from your start date before you can take the proctored final exam. I think you can take the final exam anywhere - they have arrangements with various local colleges re proctoring.
I'm not thrilled with the P. class thus far. It's basically a syllabus that just tells you to read the textbook, chapter by chapter, in sequence, doing worksheets, writing/discussion forum assignments and quizzes along the way. There seems to be very little content contributed beyond that (no lecture powerpoints or audio or video). There are brief notes to accompany the reading, but they are very brief. I'd prefer a bit more distillation of what is really critical, as I would prefer not to have to memorize every minor detail in the textbook. The way it's set up, I'd say it's way more work than an in person class. Certainly it's not a cakewalk.
Beware that some schools don't let you take online stuff for prereqs. I'm just taking these as additional classes, so that's less of an issue for me.
And if you want to take an in person class, you might try to find a school on the quarter system, and see if you can enroll for the coming spring quarter.
Also, I believe that BYU offers an extensive selection of online courses, and they may be slightly less expensive.
