My objection:
Eventually you'll have questions. It's not easy to answer questions in math via e-mail. You're right, anything experimental would be harder <g> but even math often requires face time with a chalkboard. I've found trying to answer questions via e-mail, especially mathematical questions, difficult.
Also, I find that for abstract topics, self-teaching is not easy -- and that's something I've been doing all my life. It is *much* easier in a good lecture to stop the instructor and ask a question for immediately clarification. Otherwise you are reading on and wondering, what does that symbol mean, and feeling more and more frustrated. Unless you are genius (see
http://quanta-gaia.org/reviews/books/FeymanJoking.html ) it doesn't work out well.
PS -- I'm not trying to tell you not to do this. But be aware it will be harder, much harder and probably more frustrating, online than in person. True, you'll skip the bad lecturers, the ones you can't learn from anyway. But you'll miss the good lecturers. the ones with true value-added insight, as well as the peer tutoring from interacting with fellow students.