I want to rehabilitate my old Dodge Class C

Frankedj wrote:
With 20 years of experience in construction you know that you will find the unexpected. Using one of those saws to cut through ceiling and wall panels without knowing exactly what is in that ceiling or in that wall can cause considerable damage to wiring that might be in there.

You will also have to add additional framing at every cut edge to have a surface to attach the new panel to. That is also going to reduce the structural integrity of the whole unit. You would be better off to pull out the cabinetry and replace full panels with full panels. If you want your repairs to last you should do them as close to original as possible if not stronger. Never go the route that will be weaker or do it because it is easier. You will end up paying for it in the long run with a job that needs to be done twice instead of once.

Styrofoam insulation is what you were thinking of.

Well, I thought it was "styrofoam" but the web site's spell check kept flagging it--probably because I didn't capitalize it.

The "oscillating tool" (it really needs a more zingy name), used with a delicate hand, will cut only just as deep as you want and no further, so I'm not worried about damaging any wiring.

I used to do bathroom remodels. If they just wanted new tile over their tub or shower, I learned how to take out those sections of wall in one piece (as opposed to just demolishing them) without disturbing the surrounding walls. Surgical precision and patience were required, but it really payed off.