Managed to spend a couple hours wrenching on Preposter.us and it's already starting to look better!
One thing I'm particularly impressed with is the way the new layout formats posts with a lot of photos. It will be interesting to see how that works when there's more text and images interspersed, but right now I'm pretty happy with it.
I'm also happy that I'm no longer using a custom font, and didn't have to resort to loading external/remote fonts. In fact, right now Preposter.us doesn't load anything from outside of its own server (as it should be). There's still some things about the design I'd like to improve, but overall it's getting better faster than I expected, so much so that I might be ready to start talking about the project more publicly soon.