I given some thought to all the comments before posting e.g. 17-40, CPL, macro lens, interior shots, etc. and realizing that I'd just have to take both bodies. Having both FF and crop bodies would keep lens changes to a minimum while giving me more flexibility.
I just returned from a local car wash (need to get the car washed from recent road-trip along the coast).
I observed how the light is hitting chrome trim and glass from different angles, reflections and such. CPL outside in the sun should really help.
Either later today or tomorrow, I'll visit a nearby auto mall and ask the dealership sales staff if I can photograph the cars on the lot and inside the showroom to get some practice.
Excellent! CR is a really good place to get the photographic juices flowing.