I suggest everyone read their manual, for their particular fridge.
We run ours non-stop once the cabin is up to temp. Cabin thermostat keeps the camper 55-60 degrees F when up and about, and a bit lower when sleeping.
According to the manual for our CR-1065, the fridge is designed to operate in a temp range of 18-43 degrees C. Or roughly 65-110 degrees F.
These are the best numbers I can find in the manual. And do realize, the way it reads, these are not actual operating temps.
I see this temp range as the range the fridge will operated most efficiently at, without problem.