I've got a standard RV type fridge at our camp, there's no electricity (other than a generator) and no way to precook it.
Years back we came up with a method that works really well.
Freeze a several (we use 4) of the largest plastic (not glass) soda bottles full of water in your freezer at home, then stand them in the fridge and freezer (we put 3 in fridge, 1 in freezer) with one of those battery-powered fans in there.
We can have the fridge down to 45 deg in about 1.5 hrs. The food lives in the cooler till then.
Afterwards we put a little water in the cooler with the frozen soda bottles and use that to chill the drinks for the rest of the stay.