Lets hope it doesn't get to that point, because superman as he is now is a bit absurd, let alone as he was originally. Besides, the only real power increase that would be necessary for Goku to stand a chance at winning would be for Goku to be less dumb, or less insistent on fighting people at their full power. He did after all figure out that superman's power comes from the sun. Instant transmission is as OP as anything else. I don't even think he'd even have to move the fight away from planet earth. In the scenario they presented, it would've been sufficient to just use instant transmission to intercept superman as he tried move the fight above the cloud cover.
It's true, so he'd resort to psychological ones like deception or distraction. Goku is notoriously weak against those.