1st Area 2nd Area 3rd Area 4th Area
The Safari Zone should be your next stop and you'll find yourself coming back quite a few times in order to catch all of the Pokémon inside. You'll find tons of items including the HM03 Surf and the Gold Teeth which need to be returned to the Warden.
The Warden lives beside the fishing guru and will reward you with the HM04 Strength.
To enter the Safari Zone you must pay $500, and the first area you'll come to is the entrance that'll connect the three areas.