LS Swap Fuel System Help

[GSD Guy]

Hi, I bought a Blazer a while back that has been mostly sitting in my garage because of a fuel leak and lack of time. I finally started to track it down and would like some advice on what to do. It was swapped with a 5.3L prior to me owning it but the fuel system routing doesn't seem that great. It has what looks like a stock style tank with an inline fuel pump that pulls from a stock sending unit (which doesn't seem to be reading correctly either).

The return line is soft hose until in front of the rear axle where it then connects to the evap system vent line that would normally go to the charcoal canister (the charcoal canister is no longer in place). From there, at the back driver's side of the tank, the end of that hard line is connected to the passenger's side vent hard line which is connected to the passenger's side vent on the tank so this is where the fuel is returning to the tank. Seems like a roundabout way to return fuel to me, but again, not my work.

The driver's side vent is connected at the tank to the hard line which is then open at the rear, so obviously when gas is sloshing around it's coming out of this line. None of the three lines are connected to the container in the bed but I can't just connect this line because the evap system is no longer intact. My question is, can I just cap the driver's side vent at the tank and get a new vented gas cap? And following up to that, is there an easy plug to cap that with and are the stock 72 gas caps vented? Or will I need one from another year prior to the evap systems?

Thank you everyone!!!!