After waking the Snorlax that was blocking Route 16, you can pass through the gatehouse to reach Route 17.
Explore the Route
Go south, and if a pokémon is following you, you will find a Silver Pinap Berry in the flowers.
Go to the northwest corner of the route, near the streetlight, and check the flowers to find a hidden Pinap Berry.
Go east, then south, to find a Super Potion in front of the benches.
Check in the flowers south of the benches to find a hidden Silver Razz Berry.
Go west from the benches and you can battle Picnicker Dalia, who has a level 37 Vaporeon. You get 740 Pokédollars and 2 Great Balls for winning.
Go south from the benches and you can battle Beauty Alexis, who has a level 37 Jolteon. You get 2220 Pokédollars and 3 Poké Balls for winning.
Go south from the Beauty and check in the flowers south of the benches to find a hidden Razz Berry.
Go west from the Beauty and check in the flowers to find a hidden Pinap Berry.
Go south from there and you can battle Lass Mila, who has a level 36 Flareon. You get 720 Pokédollars and 3 Poké Balls for winning.
Check in the flowers southwest of the Lass to find a hidden Pinap Berry.
In the grass south of the Lass, you can encounter Doduo, Dodrio, Ponyta, Rapidash, Pidgey, Pidgeotto, Psyduck, Raticate, and others.
In the northern part of the grass, there is a Super Lure.
In the southern part of the grass, on the left side, there is a set of 3 Great Balls.
In the flowers southwest of the grass, there is a hidden Razz Berry.
East of the grass, you can battle Ace Trainer Johnson, who has a level 40 Wartortle, a level 39 Magneton, and a level 39 Marowak. You get 3900 Pokédollars and 5 Ultra Balls for winning.
Go south and check between the yellow flowers near the wooden sign to find a hidden set of 5 Nanab Berries.
South of the wooden sign, there is an Elixir in the grass.
Check in the flowers south of the grass to find a hidden Razz Berry.
To the south, the path splits in two. You can go down the left path to battle Punk Guy Corey, who has a level 38 Primeape and a level 38 Graveler. You get 1064 Pokédollars and 3 Poké Balls for winning.
South of there, check in the flowers to the right of the Coach Trainer to find a hidden Pinap Berry.
Talk to the Coach Trainer and you can battle Coach Trainer Grantley, who has a level 40 Fearow, a level 40 Beedrill, and a level 41 Sandslash. You get 4100 Pokédollars for winning. After the battle, you get TM58 Drill Run.
South of the Coach Trainer, there is a Rare Candy in the grass.
South of the grass, there is a patch of flowers on the left that has a hidden set of 3 Silver Razz Berries.
Go east from there and check in the flowers to find a hidden set of 3 Razz Berries.
Go southwest to find a set of 5 Silver Pinap Berries in the grass.
Go south and check in the flowers to the east to find a hidden set of 3 Silver Pinap Berries.
Go west, then go southwest from the wooden sign and check in the middle of the flowers to find a hidden set of 3 Nanab Berries.
Go south and check below the benches to find a hidden set of 3 Silver Nanab Berries.
Go north, then east, to find a Nugget.
Go south and you can battle Beauty Samantha, who has a level 37 Weepinbell. You get 2220 Pokédollars and 3 Poké Balls for winning.
Go southwest and you can battle Gentleman Orson, who has a level 38 Persian. You get 4560 Pokédollars and 3 Poké Balls for winning.
Go southwest to find a Super Repel behind the benches.
East of the benches, you can battle Picnicker Misaki, who has a level 37 Vulpix, a level 37 Ivysaur, and a level 37 Wigglytuff. You get 740 Pokédollars and 2 Great Balls for winning.
Go southeast and check in the flowers to find a hidden Razz Berry.
Go northeast and you can battle Ace Trainer Maria, who has a level 40 Exeggutor, a level 39 Ninetales, and a level 39 Starmie. You get 3900 Pokédollars and 5 Ultra Balls for winning.
Your next destination is Route 18.