I used a dorm fridge for years and it was great.
Some shed heat through coils, or a grid, on the back. Many don't have that and shed heat through the walls on the sides of the fridge, which happens to be less efficient but doesn't matter unless you are working off of batteries and want to conserve electrons.
If you're going to cut holes out of the shell you might as well install the vents that are for a propane fridge so that part is ready for a 2 way if later that makes sense.
Or, instead, people leave gaps around the sides and top of the opening they slide it into to allow air to flow around it.
If you want to run it off batteries, you can, but you will need a substantial size pure sine wave inverter (the more expensive kind), and a substantial battery
bank. If you go that route there is a fair amount of learning involved and a financial commitment that will have you more than half way to a 2 way fridge. My first battery
set-up used a 2000 watt pure sine wave inverter with 4 golf cart batteries (430 amp hours) and it was good for a 3 day weekend boondocking
Before that set-up we'd just plug in easy and cheap. For the odd trip that didn't offer electric we'd pack a cooler like the tent days.