In fact, nearly all of the energy expended by modern rockets goes into lifting the rocket fuel itself, and only a small amount into the payload. Which would me

In fact, nearly all of the energy expended by modern rockets goes into lifting the rocket fuel itself, and only a small amount into the payload. Which would mean the fuel needed is quadratic in the GPE needed, which would put Saturn right back up there at ~100 times harder to reach than the moon (ignoring constants).