Im not sure if glassing the cabinets in permanently is something I'm into
Usually when people say this, they mean only tabbing in (with fiberglass) some wood supports that the cabinets can be screwed into, rather than having to be attached through the outer shell. Basically the equivalent of how the dinette benches and front bunk are attached.
Still waiting on the weather so I can finish off the floor, then the shell can come off the frame. I ordered a new Atwood everest furnace so will have some heat for the chillier nights.