After a rest at the Snowbound Lodge, you head north to Route 217.
Explore the Route
In the grass in Route 217, you can encounter Machoke, Meditite, Noctowl (night only), Sneasel, Snover, and Zubat (night only).
Go north and you will battle Ace Trainer Dalton, who has a level 34 Raichu, a level 38 Hippopotas, and a level 36 Pelipper. You get 2432 Pokédollars for winning.
To the northwest, you can battle Skier Madison, who has a level 37 Snover. You get 1480 Pokédollars for winning.
Northwest of Skier Madison, there is a hidden Nugget.
To the east, there is a hidden PP Up.
East of that, you can approach the pile of snow to battle Ninja Boy Antonio, who has a level 33 Zubat, a level 36 Croagunk, a level 33 Golbat, and a level 34 Zubat. You get 576 Pokédollars for winning.
To the east, you can battle Skier Shawn, who has a level 34 Snover, a level 34 Golduck, a level 33 Snover, and a level 35 Snover. You get 1400 Pokédollars for winning.
Northwest of Skier Shawn, there is a bottle of Iron.
West of that, there is a hidden Calcium.
North of that, you can approach the pile of snow to battle Ninja Boy Ethan, who has a level 35 Skorupi and a level 35 Golbat. You get 560 Pokédollars for winning.
Northeast of the Ninja Boy, there is a hidden Protein.
North of that, there is a TM07 Hail.
To the east, there is a hidden Ultra Ball.
Get Rock Climb
There is a house to the northwest, and north of the house, you will find TM100 Rock Climb. However, you can't use it outside of battle until you get the next Gym Badge. But you should pick it up now, to make sure you can use it outside of battle later.
Now that you have TM100 Rock Climb, go back into the house and talk to the hiker to get an Icicle Plate.
Continue Exploring the Route
East of the house, there is a hidden Max Repel.
East of that, there is a hidden Max Potion.
To the north, you can battle Skier Bjorn, who has a level 36 Mantyke and a level 38 Sneasel. You get 1368 Pokédollars for winning.
Near the Skier, there is a hidden Max Revive.
Go west to find a hidden Ultra Ball north of the hiker's house.
To the north, you can battle Skier Lexie, who has a level 35 Marill and a level 35 Clefairy. You get 1400 Pokédollars for winning.
Go east and there is a house to the northeast where you can talk to the person to get a Spell Tag.
North of the house, there is a dead end with an icy rock.
Go west from the house, then north, and you can battle Black Belt Luke, who has a level 36 Croagunk, a level 35 Onix, and a level 37 Machoke. You get 1184 Pokédollars for winning.
Go north and follow the path. As you go north, you will battle Ace Trainer Olivia, who has a level 37 Roselia and a level 37 Seaking. You get 2516 Pokédollars for winning.
Go north and you will reach the Acuity Lakefront.
In the grass at Acuity Lakefront, you can encounter Machoke, Meditite, Noctowl (night only), Sneasel, Snover, and Zubat (night only).
Grunts are blocking the path, so go east. When the path splits, go north first to find an Ultra Ball. Then go south, then east. You will reach Snowpoint City.