Thanks for the tip Rusty, I've used the Krylon plastic paint with success before; for this I think I'll probably borrow some of my son's Testor's model paint.
You can't really tell from the pics, but the plastic is really UV degraded; I'm going to thin some epoxy and put on a couple thin coats to fill the porous plastic and then some bondo to level the imperfections. I'll post some more pics when that's done.