My 1980 Trillium
13 came with no fridge as it was taken out, so going over lots of options/cost/dry vs plugged in camping, here is my solution.
Walmart "Yeti" Type cooler
One for food
For Drinks and Fruit, opening many times per day
Walmart Chinese mini fridge Galanz
3/4" foam insulation
see second photo, foam cut and installed three sides, locking in fridge in opening and providing more insulation. NOTE Clearance at back for the "dorm fridge" heat to escape
Duracell 1100 power station
Can dry camp for three days,
then a campground to plug in for the night
use the Galanz fridge, which does take time to get to 40 degrees
Stop and get some more ice
then either stay or go back to the woods.