The Fossil Maniac's house is located a short distance away from the city. Enter the house and talk to the guy there to receive a TM28 Dig. After that, leave the house and continue along the path. You'll find a gentleman along the way who will give you the TM08 Roar.
Continue to the south and you'll find two fishermen that you can challenge to battle.
Fisherman Claude (Reward: p672)
Fisherman Nolan (Reward: p736)
As you cross the bridge, there might be a Swablu flock flying above. Make sure to scan them using your DexNav if you can. After crossing the bridge, head to the left and examine the lone patch of flowers near the water's edge to get a hidden Revive. Next, go to the right and go behind Lanette's house to the right and past the grass patches to find berry trees. Harvest Aspear Berry x6 from them.
The man outside Lanette's house can also give one random berry per day. Enter the house and talk to Lanette to get a Lotad Doll. Talk to her again to re-organize the "Organize Boxes" in the PC Menu. You can talk to her again to change that. Leave the house and continue south. Here, you'll encounter more trainers.
Teammates Tyra &Ivy (Reward: p1,104)
After defeating them, go to the deadend to the southeast and find a hidden Carbos. Head to the left to fight another trainer. Go upstairs and smash the rocks to the north to reach the Protein at the end of the path. Backtrack and continue south.
PokeManiac Steve (Reward: p644)
There's also another Secret Base entrance there. You'll spot May/ Brendan pursuing the abductors to the south. Continue forth and fight another trainer.
Camper Shane (Reward: p320)
Search the middle of the smaller crater to get a hidden Comet Shard. Next, search the larger crater to get a Rare Bone.
Go to the right then go north along the narrow path beside the stairs. This will lead you to an Energy Powder. Go upstairs next. There's a Secret Base entrance once again behind the smashable rocks.
Walk a short distance to the right to find yet another Secret Base spot. Continue to the south and challenge the following trainers.
Kindler Bernie (Reward: p704)
Hiker Lucas (Reward: p640)
Go uphill and walk past the giant crater. You'll face the last trainer in the area before you go downstairs.
Hiker Lenny (Reward: p736)
There are two more Secret Base entrances you can find in the area. One is directly to the south of the stairs past Hiker Lenny. And the other one is behind a smash-able boulder next to the cave entrance.