Fridge -Replacing Norcold With Home Style Unit

I am trying to understand how the home unit like the Samsung is used on the road since you are not using propane to run it while movng down the highway for several hours. Do you constantly run the generator ? Carry nothing in the fridge until you arrive at a RV park ? Maybe run it for awhile and then turn off the generator ? If so, does the food and frozen items stay at the necessary temps ? Thanks for any advice.