If there is no basement, seek shelter in a small interior room in the middle of the building, like a closet or a bathroom. Always stay away from outside walls and windows. Opening windows to equalize pressure during a tornado is ineffective in reducing damage. Also, flying glass is a real hazard. You can outrun a tornado in a car.
Mobile homes are safe if they're tied down.
A mobile home is never safe in a violent windstorm such as a tornado. Or be prepared to take cover in a low area, covering your head and the back of your neck.