Looking good GHarless!
Something you could do for upholstery, is what I did for Lurch, my '27 one ton truck. I made a bench seat bottom from the ends of a twin bed box spring and covered it with an old jeans skirt of my wife's. That was 25 years ago and it still is holding together.
For seat backs, I took one of my pair of old jeans, cut them in half (along the side seams) and stapled them to pieces of plywood with some foam for cushoning. So, the driver's seat is the front of the jeans and the passenger's seat back is the back of the jeans.
Crowd pleasers wherever I go.
Cheers, Dean