How have I never discovered Bondo before? I thought it was used exclusively by auto body shops, but I watched our carpenter using it to fill and fair the floor and walls after demoing our old nav station. The stuff is amazing. I've been using West System 410 Microlight for these types of jobs, but the epoxy is much harder to work with and takes longer to cure. The Bondo can be sanded within minutes, which greatly reduces the fill-sand-fair-sand-paint cycle.
I might actually get more painting done now…. well, at least the fairing and sanding part. I had to kick T and kids off the boat for 24 hours for the last painting project. Partially because of the fumes, and partially because if there's wet paint around one of them is bound to put a hand (or worse, a foot) in it.