For a few weeks of camper use per year, gas is the way to go.
If you do thousands of miles hauling a camper year after year, maybe never taking the camper off, diesel is the way to go.
Why? It's that hay hauling truck creeping up grade ahead of you - about a quarter mile ahead and doing 15 miles per hour. You see the highway narrows to one lane ahead due to construction.
Do you want to fall in behind the hay hauler at 15 miles per hour for the next 15 miles of uphill grade? Or do you want to pass before the lane narrows?
Diesel will do it. Gas, maybe if it doesn't throw a rod.