We've already been working locally at a local domain (v10.whatup). Now it's time to get started moving into WordPress. We're going to keep working locally at a local domain, but we're going to start using the already working local install of CSS-Tricks I have (css-tricks.whatup).
We start by just duplicating the existing WordPress theme in the wp-content/themes/ folder and renaming the that theme folder "CSS-Tricks-10". Might as well give ourselves a base to work with. A quick guess: maybe 50% of the code of this theme will change. There is a good bit of code that just doesn't need to change, like the templates that create special RSS feeds.
We change the bare minimum of things to activate this new theme: the screenshot.png file so we can visually see which theme we are activating and comments at the top of the style.css file that is the meta data to identify the theme.
Then we activate the theme. It's a mess, as expected, but now we're ready to start making our static mockup into our final product: a real live WordPress site.