Auto Union - Work in Progress

I wanted to do a larger work of Hans Stuck racing his C Type Auto Union up the Grossglockner mountain on his way to becoming German Hillclimb Champion in 1938. My Grandfather was there and took this photo of him at the start...
www.pbase.com/smarjoram/image/3472160
I made a basic model in Maya and exported a wireframe - mainly to get the wheels right but it also allowed me to quickly experiment with camera angles.
This pencil sketch is A3 (pretty big for me). I tried one twice the size - transferring it to some card - only to find that the card wouldn't take any sort of paint or crayon without going wrinkly or showing the ridges in the card.
Next stage is to try again with a more suitable paper - perhaps using some charcoal. I may also try a digital paintover on this pencil sketch.