-made some progress, got the plastic bath parts (except the ceiling, which will be done in place) patched and painted...for the patching I used this new product from West Marine called G/Flex, which comes in a 20-buck kit:
and bought a couple extra feet of 4" fiberglas fabric. mix 1 to 1 and glop it on. the great thing about this stuff is it really is more flexible than regular epox/fiberglas and that can only help in a twisting/turning airstream... here you can see what a patch looks like on the backside. this was one of the nastier cracks which you can see earlier in this thread..
here's how it looks in front..not perfect by any means but way good enough for my needs and super strong...I filled in the front-side irregularities with Interlux Watertite Epoxy Filler, which is just truly amazing stuff. it is so strong and tough. I fixed the front door of my house with it (cracks that never seem to stay patched) and it's the first thing that has actually worked on this door, so I feel ok about using it here. I'm going to also use it to patch/level the seam in my now-split sub floor (which i had to do to get it put in) ..this is that part just aft of the toilet:
I used two brushed-on coats of Interlux Brightside Polyurethane and it looks really nice and should be incredibly durable. I sanded the parts with 220 paper and cleaned with acetone. (the trick with brushing, if you don't already know this, is to always BRUSH BACK into what you just painted and raise the brush lightly to feather any strokes out... the only imperfection is from tiny micro dots of dust and/or bubbles and if anyone can recommend the best way to polish these out (Nuvite?) I might give it a shot, but they look nice as is...so I might not ;-)
here's the lav:
as you'll notice some of the parts are super smooth and others, like the bathroom above-tub cabinet have more a pebbly surface which you can see above the tub:
got the sub floor all cut out and put three coats of Aerowood-style "hybrid" poly on it (where you mix together all the random half-full cans of poly you have laying around...it works great!) and will post another update as soon as I have those puppies bolted in....