As you are aware the power cable that attaches to your truck trailer lights receptacle is just a trickle charger and if its like our camper won’t run the fridge without pulling from your camper batteries. Our solution is to pre-cool our fridge/freezer and add a few icepacks and run it like an icebox while we are on the road. If we stop for a couple of hours through the day we turn it on propane and let it cool again. Once we arrive at our destination it goes off icebox mode and back on propane and chills again until the next travel day. I guess it depends on your travel plans and how hot it is outside but this works pretty good for us.