The results: great, thanks in large part to the advice I received here.
I was able to put only one light, two cameras, and no operator in the vehicle. No tinting of the driver’s window was allowed. I used a FilmTools 494 kit to attach a light and camera to the passenger seat’s headrest support rods, providing a profile view of the driver with the background of his window. The light was an LED (Flolight Microbeam 128), set to provide moderate, subtle fill when the background was backlit, i.e. relatively dark. It didn’t look “lit” at all. I used a Flip HD, which averaged the exposure, so that the background would never look blown out.
To provide coverage of the driver’s face when the scenery outside the driver’s window was frontlit and therefore too bright for the profile view camera, I put another small camera (Sony CX150) on an interior windshield mount, aimed, zoomed-in, and spot-metered for the driver’s face, so we always had coverage for his facial expressions.
The coverage of those two cameras along with the various POV cameras on the outside of the car, did the job beautifully. To repeat, it never looked “lit” yet we got what we needed.
Thanks again. The concept of merely filling, not lighting, was the thing I needed to hear.
Bob C