Here's a guy looking to get the certifications YOU have and you say fixing a cheap boat is the best way?
Yup! I have learned WAY more in this forum, than I learned in the 12 week Marine Electrical Systems certification course. I should have added; go to Maine Sail's blog/gallery and learn from that too.
The OP didn't specifically ask for certifications (which, in my experience, are worth squat*), but he asked for a way to learn how to maintain his own vessel. Quoting the OP;
I want to learn more about taking care of our marine systems before we go - and maybe even getting good enough to make some money at it along the way. I have a year to dedicate to this learning.
The guy's got a year, and wants to learn more about everything. I believe that buying a boat, research and practice, is the best way to get there.
He also said that IYRS was on the pricy side...
* - (After graduating, I had the opportunity to work an internship: either detailing boats, or be yard monkey.)