Last time I was driving a MH, it was summer here in TX, so I was running the roof A/C and generator, so I flipped the fridge to 120VAC. Since I was using gasoline for the genset, might as well save propane.
Of course, another trick I learned is to have freezer packs in the freezer compartment (assuming there is room). Then, when you flip the fridge off, move a couple to the lower compartment and call it done. Those can last 12 hours easily, perhaps longer.