Instructions
Fly to New Bark Town. Make sure that you have a Pokemon that knows Surf, Waterfall, Whirlpool and Strength.
Surf east on the body of water in the eastern part of New Bark Town. Once you reach land, a man will come up to you and tell you to check your PokeGear, where you can see a new map of Kanto.
Go North to enter Tohjo Falls. Once you are in, surf up the waterfall and down the other side, and then exit the cave.
Surf east. Once you hit land, defeat all the Pokemon trainers. Head north to reach a large building. Enter the doors at the end of the hallway to reach Victory Road.
Go through Victory Road. Once you are near the exit, your rival will battle you. After the battle, exit the cave and go through the doors of the Indigo Plateau.
Heal your Pokemon and stock up on healing items. When you are ready, go through the northern door to challenge the Elite Four.
Defeat the Elite Four. You will then be taken back to New Bark Town. Talk to Professor Elm to get the SS Aqua Ticket.
Fly to Olivine City and board the SS Aqua. Once you get off the boat, you will be in Vermillion City in Kanto.