After defeating Saturn, you must...
- Lake Verity: beat the Galactic Grunts and Commander Mars.
- Mt. Coronet—>Route 216: go through Mt. Coronet and exit to Route 216.
- Route 216—>Route 217—>Acuity Lakefront—>Snowpoint City: collect the HM Rock Climb and then go east (right) to Snowpoint City. You can't go into Acuity Lakefront yet, so just go to Snowpoint City.
Um, did I clear it up for you?