I'd recommend if you want to learn how Claypool does it, watch him do it on the "Animals should not try to act like people" DVD.
One thing that's slick about this tune, the strummed part transitions really smooth into the fingerstyle part of the riff. It's Downstroke, Upstroke, Downstroke, and on the next upstroke you naturally set yourself up for the fingerstyle part of the riff. This is my first attempt at playing it, so I just realized that... smoooooth.
