ROOF PAINT, ETC.:
Did some looking around after the HyTech suggestion (thanks!), and made a few choices.
To treat the ceiling & inner walls & frame, I bought a gallon each of the Por15 Cleaner/Degreaser, Metal Prep, and Por15 (in clear). I'll treat the exterior rust areas first, top to bottom, then coat the ceiling, interior walls & frame with the Por15.
I'm going to paint the roof & gutters in HyTech's 'Bus Kote' white. It sounds pretty thoroughly sealtastical when it's on, it's thick, and contains the ceramic beads already. I bought two gallons, so I'll apply 2 coats to the roof, and if there's any left over I can use it for the inside walls before I insulate & board them over.
After that's on, I'll splash a layer of their 'Flexi Clear' over the roof/gutters to seal it. Bought one gallon. Hopefully that will be more than enough.
I bought a gallon of the HyTech 'Barrier Kote,' which is advertised to act like a vapor barrier via the overlaying aluminum flakes in the paint. I'll use that on the ceiling & walls. After that, it's time to insulate & start throwing up the ceiling & side panels! (After the plumbing/electrical has been figured out, of course!)
Fun topic & different for everyone it seems. Different R-Value needs, space to work with, budgets, etc.
At this point, I'm looking at steering away from the spray-in foams. I love the compactness & thoroughness in the application, getting into all the books & crannies...I just don't feel comfortable living in such a tiny space with the gases it MIGHT emit. It may...it may not...it really hasn't been around & been tested long enough to know what it does, good or bad.
So I'll be looking at hemp insulation. It comes in boards of different thicknesses, as well as loose filler you can stuff in the nooks & crannies. I like that it's natural, has been treated with only 100% natural ingredients, lasts forever & repels moisture. So, with some time to still do some research before it goes in, that's my leading choice! Has anyone had any experience with Hemp insulation before?