That’s my site. The short version is, you can make it work in onecol layout if you’re willing to go through and edit a whole bunch of CSS to make the board fit. I copied in my entire stylesheet in the link to give you a headstart.
All I do is use Chrome’s Web Developer extension to individually ‘inspect element’ on each piece of layout that I need to change, then go copy that element’s CSS tag into the Theme Options/Layout section of Pinboard. Pinboard’s stylesheet there will load last and therefore override all earlier CSS, allowing you to make changes which stay consistent after updates, for the most part.
As far as I’m aware I’m the only one who’s taken the time to make bbPress work with Pinboard. I also used a Multisite setup so I can use Pinboard’s core functions on other parts of my site.
You can see it here:
itinerantangler.com
Right now I am working on trying to figure out how to make the slider scroll on every sub page instead of just home pages.