After passing through Route 9 on your way to Rock Tunnel, you reach Route 10.
Explore the Route
In Route 10, you can encounter wild Rattata, Raticate, Spearow, Fearow, Nidoran♀, Krabby, and others.
Go east past the grass to find a Super Potion.
Go southwest and jump down the ledge, then go to the left and check the ground near the corner to find a hidden Super Lure.
Then go east and south toward the Team Rocket Grunt. After a cut scene, you will battle a Team Rocket Grunt who has a level 22 Raticate. You get 616 Pokédollars for winning.
Go into the nearby Pokémon Center if you wish.
If you want to skip a trainer battle, you can chop down the trees to the left of the Pokémon Center.
Otherwise, south of the Pokémon Center, you can battle Camper Vance, who has a level 22 Eevee and a level 22 Psyduck. You get 440 Pokédollars and 2 Great Balls for winning.
Go southwest of the Camper and you can find a set of 5 hidden Poké Balls in the corner.
Go north and you can battle Coach Trainer Tasha, who has a level 25 Poliwhirl and a level 26 Primeape. You get 2600 Pokédollars for winning. Afterward, you get TM13 Brick Break.
Go east from the Coach Trainer to find 3 Great Balls.
If you are ready, go into Rock Tunnel.