Do you have any recommendations for embarking on that path of hard, self-directed work?
My co-founder at http://8-food.com/ and I are at the earliest section of that path right now and - while we are attempting to optimize for manufacturing by assembling primarily from pre-existing commercially available components - do recognize the need to improve our presently nearly nonexistent mechanical engineering skills.
In your case you are either trying to deliver a product or educate yourself. It is very, very hard to do both. Particularly if you are, as you said, starting with "nonexistent mechanical engineering skills". A lot goes into a product that is reliable, durable and manufacturable. This would take a lot of time and errors to learn. A better formula is to hire someone or a company well versed in that part of things. Focus on your core competency.
People like me are able to do what we do because, at some level, we are a product of a different generation. I was disassembling and rebuilding engines and modifying cars in my driveway when I was 16 years old. I designed and built my first computer from raw chips when I was 18 and wrote my first OS out of hand-keyed hex machine codes afterwards.
Today I've worked with young engineers who openly admit not being good at soldering and know PhD's who have trouble assembling Ikea furniture. Not sure what it is, but it sure seems engineering is being done differently these days. Back then, if you went into any of the engineering fields it was very likely you tinkered ad nauseum way before hitting college. Not so these days.
What I am saying is that as an electrical engineer by schooling I had already done tons of mechanical, software, optical and other work and picking up some aspects of these other fields over the years was an organic process. Starting from "nonexistent mechanical engineering skills", well, that's a bad place to start. Driving CAD isn't going to make you a mechanical product designer.
My co-founder at http://8-food.com/ and I are at the earliest section of that path right now and - while we are attempting to optimize for manufacturing by assembling primarily from pre-existing commercially available components - do recognize the need to improve our presently nearly nonexistent mechanical engineering skills.