Can I put stuff in my car when I ship it?

The straight answer is no. The Department of Transportation does not allow the transport of personal belongings inside the vehicle during transport. They do randomely inspect the vehicles depending on the route. However, many people put personal belongings inside their cars and most drivers will never say anything about it unless the vehicle is packed to the top. Then they may ask you to remove the items or to pay them a surcharge for transporting it for you.