Nice! Brings back memories....
I have a tip/what I did, to move the fiberglass bathroom in one piece.
Finish removing all the cabinets and paneling so there is nothing in the way. Get your sawzall and cut the return flange in the vent area (a new vent 14 x 14, can be installed and the trim ring will cover your cut) flush with the top of the bathroom ceiling. With the plumbing fittings removed on the floor, you're ready to slide the bathroom out of the way.
It is tight, you will need another helper that can "shoulder press" the roof beams to create some wiggle room. I could only move it to the the isle way and just inside the wing area. This opened up the bathroom area for repairs to the frame, new flooring, etc. One you're done, slide it back!
Remove all (as many as you can) old screws, they rust and thin down and allow water to enter. Add bracing to those upper back corners tying the 2X6's to the 2x2's, this is where the "sag" comes from. Only a few screws hold this structural area, they rust and the back shifts down from the weight of the floor/snap n nap.
Looks like you have the tear-down figured out.....
Good luck with it!! I'll keep looking for your updates!
If you have any other questions, hit me up, glad to try and help.
Dave
