Another issue with a slide in camper is the high center of gravity: When you hit the gas, truck accelerates under the camper, causing an extra rearward tilting force on the frame. At the same time, the truck grips on the asphalt trying to turn the wheels forward, thereby putting a reaction force on the frame, further increasing the bend back over. A pickup is not a truck, its a light commercial vehicle, built to a weight, and designed to take payload with its CoG only slightly in front of the rear axle so the front axle doesnt carry much other than occupants and drivetrain.