Go with an Anderson connector, minimum of 100A though the cost is about the same for a 175A connector. Upgrade to 2 awg and use welding cable as it will be flexible yet resistant to uv and oil. Find a place you can drill one or two holes through the camper exterior to where you want the truck side plug. Let the camper side just dangle with enough slack to where every you plan on solid mounting the truck side. Since my battery is in the back of my Lance 815, I mounted the truck side in my rear bumper and the camper side goes from the battery right out by the tail light. You will want the battery cable to go to a breaker than to the DC-DC charger which will then get hooked up to the battery.
