I think it matters if they're going back in. When I've done home remodels the way I take stuff out that isn't going back in is usually pretty direct. Mr. Cabinet I'd like to introduce you to my friend Mr. Sawzall.
The little bit I've messed around in my RV, "cabinet" is a bit of a misnomer. More like a frame with trim, a door, and maybe a panel on one side. I would start with taking all the doors off to make it lighter and I suspect using pocket screws or under button covers you'll find what's holding them up.
Mark B.
Albuquerque, NM