This is great, and thanks for writing it up. I don't think many graduate students would consider doing this right after graduation...I certainly wasn't in a mood to write another detailed document after getting done with my dissertation (also a couple of months ago, and in computer science).
I wanted to add a little about the end-game. For me, the decision of what to do next followed a slightly different path. In the fall of my 5th year, while planning to graduate, I had to really think about what to do next. Academia sounded interesting, so I went ahead and applied to tenure track jobs, and did interviews. Come winter, I had an offer from an Ivy League school. But I had also wanted to do startups for a while.
From my experience, working on projects that were not provided/sanctioned by advisors was somewhat like working on a startup. You have to build things that others find useful/interesting, sell the crap out of it in publications, presentations etc, and I also had to fund it.(my research was building systems software that improves user experience in poor network environments, like those common in developing regions. One of the definite perks was travelling lots and deploying stuff I built.)
In other words, I have no idea why most PhDs are not be expected to go work on a startup when they finish. They are domain experts, and are expected to be good communicators when it is all said and done.
So, when it came time to make the call---an assistant professor, or a startup founder---I chose the later (and disappointed my advisor). Some friends tell me I could have done that without a PhD, and it was a waste of time. I think a PhD naturally leads to a start up. The Grind, as the op calls it, is something that teaches you a lot about yourself, and surrounds you with some of the smartest people you'll find. Your job, every single day, is to innovate [with a more flexible runway]...and you can make (and learn) a lot out of it.