Our outside kitchen set up looks like yours. On ours, the back wall behind the fridge is vented to the inside of the camper. It is situated under the bunk beds, and has a “wooden” 12”x12” louvered cover over the hole in the wall. The only change I did to Keystone’s setup was to sandwich screening between the wall and the vent cover so bugs couldn’t get in when we have the outside kitchen door open. I don’t know if it’s a possibility to add that vent in the wall to yours, but it seems to work great with our little fridge.
2019 F-350 DRW diesel 4x4 CC LB, still the mom taxi
2016 F-350 diesel 4x4 CC LB SRW, mom taxi - sold
2014 Cougar XLite 28RDB