I'm surprised that more people haven't been talking about this book (or maybe I've just missed it). I know this post is old, but I'm gonna post here anyway...
I'm about 3/4th of the way through A Guide to the Good Life, which is the book mentioned in this article.
Reading through it you can clearly see that it's almost 100% Mustachian, or rather, Mustachianism (or Pete, really) is almost 100% Stoic. It's kind of cool reading the "source" documents of the Mustachian philosophy in a way. I learned a lot from reading the book, despite being a long-time Mustachian. The author lays out actionable tips for your life, too, which is really sweet (and parallels the advice on this blog).
I can see why Pete calls it "Badassity" now. Stoicism is definitely badass.