YES, never use the winch as the forces on it on rough roads will either break the gears and/or pull the cable/rope into the windings.
Always the safest for any vehicle is to be tied down by it's wheels and allow the vehicle's suspension to operate on all those bumps. If you must use something else, use the frame or a-frames on all four corners with enough pull-down that it can not move in any direction...especially down on impact with a larger bump as the return may break a strap. Never on any racks, plastics or support bars...they can't take it.