1970 California Only ECS info for reference.

https://www.allpar.com/threads/fixing-1970s-and-1980s-fuel-evaporation-control-systems.229057/

To bypass the ECS system I think a vented gas cap is all you would need as the ECS cars have a special for those cars non-vented fuel cap and fuel tube combo. I think I would leave it functional and fix it ,assuming it needs fixed. I'm not seeing how a vapor return line gets clogged up though???

The vapor separator tube is just a tube with rubber lines inside it. Not really a wear item.