49719 is the cooler loop. Right at the front, LHS of that diagram.
Return line from rack (LP side) goes to cooler loop on RHS front of car, then back under engine and returns to bottom of tank.
49717M is feed from tank to pump.
HP line out of pump is thick rubber, followed by the hard line that runs down to crossmember and runs in parallel (but opposite flow direction) to the LP return line.
Nothing goes anywhere near the firewall or interior of car. The closest they get to that is the connections on the rack.