You can attach a CB antenna to wood or plastic for that matter and make it work. They need a " groundplane" which can be made by attaching wires to the base of the antenna and running them to the 4 corners of the van. When I drove cars across the US for a living back in the 70's when CB was in it's infancy I used to use a piece of aluminum L bracket and just drill 2 holes into it and screw the antenna into 1 side and the other hole I'd find a place to remove a bolt from a bumper, or if the car had a metal roof rack I'd put on a hose clamp to hold the antenna. It's not Rocket science but certain rules need to be followed for a good working CB rig. It's best to "Tune" your antenna to the car using an SWR meter.