I, literally, just did this in my '99 Widebody. I bought a "Smart Jacket" water heater blanket to wrap the heater and used the extra around the
fridge vent and I removed the
fiberglass on the fender well and still had enough of the "Smart Jacket" to completely cover the fender well and I still have a pretty good amount left over. I used actual "air duct tape" on the stock foil backed insulation everywhere it was torn or cut in the corner storage and under the countertop, around all the ports (city water) and what not. I also used "pool noodle" everywhere the glass was sagging... I pushed the noodles up into the "double wall part to pull up and hold the glass. I have been out on one trip since the pool noodles and they seem to be staying put. Anyway, between the tape and the Smart Jacket stuff there is no exposed glass and my water heater seems to work much better! I plan to use the Smart stuff to add "flap like" walls to the
fridge to try and "optimize" its performance, I'll keep you posted. Hope this helps.