I honestly believe, and I have had several people tell me this very same thought as well... that the Pinewood Derby and making of the car is meant to be a father and son or mother and son activity.
1 should not do it alone, but it should be a combined effort. I was at the Scout store here in Dallas not long ago and someone was buying the kit and was talking to the scout guy there... and he was telling the lady to make sure that this is a bonding experience between dad and son.