To go to to The Fight Area and the Resort Area and Survival Area, etc., you must first defeat the Pokemon League your first time, and then fly to Snowpoint City. If you go to the entrance and go to the ship, there will be a sailor standing there. If you talk to him he will take you to Fight Area. If you achieve all you have to do there (Battle Frontier and finish Sinnoh Pokedex), the guys blocking the entrances to the Routes will be gone. Now you can pass through.
To the east is Resort area, to the North is Survivial area, and east from there and the north takes you to Stark Mountain where you can capture Heatran.
