When I got my wagon the charcoal canister had already been removed, and the mechanical fuel pump replaced with an electric. I want to go back to the mechanical, but there 3 lines in the engine compartment, with 2 now unused. Obviously one is fuel to the pump from the tank, but the mechanical pump has 2 outlets..... one going to the carb, and the other (smaller dia) I assume goes back to the tank. Anyone have a pic of which goes where, or can describe which of the 2 is the return or vapor line?

Block the smaller return line off at hose and pump and do not use, it will bump up fuel pump efficiency, we used to do it all the time. It just bleeds off part of the pump output back to the tank.