It is only a Faraday shield if the frame and/or skin is metal. If you remain in a wood framed, fiberglass RV, and experience a direct lightning strike, it is a possibility that you will be injured or killed. Even then, if the skin is not metal, but the frame is, you stand the chance of injury or death.
If you have the camper mounted on a truck, you'd be much safer if you move into the truck itself. Roll up the windows, and move as close to the center of the truck as possible.
Even better is to move to a sturdy building and stay away from pipes, windows, doors and appliances.