+1 Jim -- Godzilla does, in fact, put that crank nut on. In my experience, the best way to get it off involves pulling the wheel off that side, lowering the engine down (after disconnecting a couple of the engine mounts), and applying an impact wrench.
Like the others mention, the only thing that's given me trouble on this job is the timing. One tooth off won't make it run terrible, but it may be noticeable, so make sure it's at TDC when you start, and then again when you're putting it back together.
And given the hassle of getting the timing belt off, I totally agree with Jim -- it's cheap, and easy, and, hey, what the heck, you're in there.
I've done a couple of head gaskets on older Hondas and (gasp) have never had the heads checked for flatness. I've also never had problems with head gaskets failing afterwards (once the original HG goes, other expensive bits of the engine are likely to fail before the replaced HG goes). Maybe I've just been lucky, or maybe the heads just don't warp very often, or very much.
Good luck, and try to enjoy it.
