1) We have done OCW and love it! It isn't nearly as easy as they make it sound, though. But, you know me, I'm a Google Master Extraordinaire and can find anything online. I realized I wasn't the only one using this stuff and others have used them too. Google the class and find out how others have used them and incorporate that into your studies.
2) We didn't do the coursework for all the classes we audited. Sometimes just watching the lecture(s) was enough to get the boys interested in learning more about the subject by finding books at their level.
3) Since you, the mom, are the teacher you can adjust the class. If a lecture is 50 minutes you can split it into 25 minute bits and use the other 25 minutes for reading or discussion. It will take longer but a college level class packs a serious punch when it hits a high school brain.
Can you see a season of stress ahead of you? I'd love to show you how to plan ahead. When you know it's coming you can survive the stress when you plan