I love seeing what people can do with Tumblr, this site is really very nice. The real-world elements and hand made sketches is what really makes this design sing.
I’m not a fan of sites where the elements are supposed to look like real objects. I think the main links could be more conspicuous and they would benefit from you-are-here indicators. Also, I don’t see why there would be two separate mail-to links in the navigation. I like grain-like background and its colour, though.
The navigation is a bit clunky on this site, probably because it’s a tumblr site, not that the fact it’s tumblr is a defense for confusing linkage.
I have to say I often like sties with real world objects worked in, that’s just me and definitely a taste thing.