I don't know the 2.3 very well, but just generally, deadheading an electric fuel pump isn't a great idea... it is hard on the pump.

I presume you're going to disable the old fuel pump (pull the drive rod?), and pump through the stock fuel pressure regulator. If that's the case, there's no need to disconnect the old return line -- just let the fuel pressure regulator divert any 'extra' unneeded fuel through the return back to the fuel tank.

Randii