Due to the skylight leak that caused it all, I actually pulled out one piece of luan and replaced with plexiglass. Probably sounds nuts, but I needed flexible and non-absorbent, and that had all the right properties for the job. Obviously, not a good choice for a whole box. But I could be wrong. There's the Popemobile, right? Anyway it was a good replacement for that one small space covering the wiring channel that goes down the center of the roof.
Now I'm looking at the space over the slide. It's metal framed, but all they really did was glue luan over it and slap some vinyl wallpaper on top. I should not know that much about it, right? Shouldn't need to. But there it is. Fortunately, it's just a dress panel. I've taken about half of it out already, but still looking for the right replacement material. The same situation applies to the inner facing of the door, where seals were left untended and the door left open during rain.
I have a couple ways to go, I think. Another type of plastic laminate, or oak (would have the slide frame redone to match that and the cabinetry). It would look much nicer than the original - more high-end Class A from that period, and would not be a difficult or expensive job for any decent cabinetmaker.
But - I still don't want wood in an area subject to any kid of water intrusion or high humidity. When you let these things sit with the slide in, any trapped humidity wants to sit up on top of the slide, which is exposed wood again - not cool. The door facing necessarily has holes in it and edges that will never remain sealed forever no matter what you do.
I like to think in terms of marine construction, or high-quality kitchen and bath materials.
Fiberglass (by itself) rocks.
Luan does not rock.
I've done stickbuilt construction and managed literally hundreds of bath and kitchen remodels, so I have a pretty good idea what happens when you choose materials and methods that degrade over time. It's not pretty! Always, always the moisture thing. Here we have a space where all are closely connected and all the living areas are subject to conditions you'd (try to) isolate to the kitchen or bath (and usually badly) in a stickbuilt. One thing we know - you can put a stickbuilt on wheels. You just can't expect it to hang together forever without help.
So now I'm looking for alternative materials that can be retrofitted fairly easily. Much as I like aluminum, it just doesn't jive with the Cutter-type design. And since I'm replacing custom pieces, I'll have to have these cut from raw stock of some kind. Criteria are: light, flexible, strong, non-absorbent, easy to cut.
All ideas welcome! I'm sure I'm not the only one.