Not sure if it helps but I have done a fair bit of scratch building for boats over the years and find photos of the real thing to be the best help as few people know what they should look like anyway.
Don’t know if you have seen it but there was a book out in late 80’s early 90,s I think it was Billards or Bzzars wooden toys and he had full plans for making a wooden American rig might be worth a look
I also found this website which has loads of photos of model and real trucks could be worth a look
http://www.rctruck.it/default.asp Hope its of some use Jay