OK. Now we know which songbook we are singing from!
"Return line". Do you mean the vapor return line?
I don't know if I have a photo of this. I will have to look around. If I remember right the bowl vent valve is connected to a hose that either goes;
a) To the breather cap (PCVS) and from there to the vapor separator above the tank.
b) Straight to a seperator canister above the fuel pump or down alongside the engine and then back to the tank.
I will see what I can find.
The fuel line itself was usually steel and ran staright up from the pump behind the alternator and to the carb. Keeping close to the block.
I will see what photos I have in books.