One thing about Kevin's trailer though, is that the Vanguard trailers did not have Ensolite. The coating, from what I know, is some kind of an open-celled foam that was sprayed on (?). So it's much "fluffier" than Ensolite, and has more of a "popcorn" texture to the surface.
Kevin, ugh, that does not sound nice.
If the insulation is open-celled, as I suspect it might be, and there have been mice living on/in it..... well that is one of the few times I'd probably be ready to strip it out and start over. That's a bold move, for sure, so don't just run out and do it on my say-so, but.... doesn't sound good.
They do still make Ensolite, just so you know. IR Foam Specialty in Washington has it. I have had them send me samples. Also, Brad and Jenny with the "Total Boler
Restoration" used it. The main difference in it compared to the usual FGRV Ensolite is that the trailer manufacturers had the companies bond a layer of "white" vinyl (or vinyl-like material) to the inside face, and that's what makes the "white" walls in our campers. What you get now is just the plain black Ensolite, and so most people paint
it (doable; Brad and Jenny did that). It's a smoother texture than the traditional camper type of Ensolite, and I see that as a plus - fewer crannies to clean.
The real Ensolite is some crazy tough stuff; I'd be surprised if the "popcorn" in the Vanguard is as tough.
PS: Thank you for confirming that your trailer is 13'
PPS: I just remembered that Roger C H posted that he knew of a source for the vinyl-coated Ensolite, but I'm not sure he identified it (I went to the link and could not find it).