Now that you have the Rainbow Badge, you can buy Ultra Balls, Hyper Potions, and Super Lures at Poké Marts (and the Trainers' Market in the Celadon Department Store). Next, you should go to the Rocket Game Corner.
Correspondingly, what do you do after Celadon City?
After defeating the Celadon City Gym, head on over to the Game Corner again and take on Team Rocket's Hideout if you haven't already!
One may also ask, what do you do after the 5th gym in Pokemon Diamond? POKEMON DIAMOND AND PEARL WALKTHROUGH. After you defeat Fantina and exit the Gym, you'll see Cynthia outside waiting. She'll thank you for the help in Celestic Town and explain that you should visit the library in Canalave City, so you'll want to do just that.
Consequently, where is the Team Rocket boss in Celadon City?
The Rocket Hideout is accessed by pressing a switch behind a poster in the Rocket Game Corner in Celadon City. A Team Rocket Grunt is guarding the poster in question when the player first approaches it.
Where do I go after Vermilion City?
You can start making your way to Celadon City after defeating the Vermillion City Gym Leader. Along the way you'll find a lot of useful items and Pokemon. At Celadon City, you'll be able to get the Silph Scope which will give you access to the Pokémon Tower.