A problem you have it is difficult to pin down exactly how much power the RV will consume. The refrigerator draws probably 350 watts max. But depending on battery charge level and installed power converter, the RV could draw over 1000 watts total.
Length of the cord is important as quite a bit of voltage drop under higher current applications. Also would be margin of safety of connector ends if they were not perfect.
I'd probably feel OK about it if I knew for certain the batteries were fully charged, or the converter/charger was turned off. And no other loads in play but the fridge.