RE: Insulation behind Dometic 'fridge
For several years I used a piece of Reflektix (bubble wrap covered with
foil, form Home Depot) on the outside of the van, placed over the area
directly behind the 'fridge.  Had a hole cut to go over the flu vent, held
with magnets taped to the material.  It seemed to help but not near as much
as the vent fan I put in that pulled the hot air out.