This has been posted on QB before, but might be a clue that it's not totally impossible - someone who sews with a hand crank while driving a tractor:
http://www.youtube.com/watch?feature=player_embedded&v=zNmztSvG-Lw
I don't think I'd enjoy trying to sew in such a cramped situation, and you can't iron (at least I hope not!). Also, that tractor is on a predictably flat, level surface and not going as fast as a car on a road. It just doesn't seem as if you'd be happy with the results of sewing in transit. As others have mentioned, there are all sorts of quilt related things that are safer and less difficult.