You'll find another split in the road. You can't get past the desert to the south due to the sandstorm so you'll need to head north. Here, you'll have to face another trainer along the way.
Ace Trainer Wilton (Reward: p1,200)
After defeating Wilton, continue north and you'll spot Aarune. After a brief conversation, he'll give you TM94 Secret Power which will allow you to make secret bases on specific areas. He'll continue showing you the basics of Secret Bases. He'll give you the Secret Base he opened and you can now design it as your own. If you don't have time to design your Secret Base, at least set up the bed. This will allow you to rest there and recover your Pokemon's health.
Once done, go to the east and you'll find a path blocked by a thorny tree. This is just a shortcut since you can reach the Old Lady's Rest Stop by going around to the north then east. This old woman will let you rest to fully recover your Pokemon's health. There's also a walking trainer that will challenge you once you get in to her line of sight.
Fairy Tail Girl Cece (Reward: p304)
Talk to the kid walking near the berries to get a random berry. She'll give you a different berry daily. Harvest the Rawst x4, and Nanab x4 from the berry field nearby. Now using a Mach Bike, climb the slope nearby and defeat the backpacker there.
Backpacker Deon (Reward: p504)
There's a secret base spot to the northeast corner. Take note that you can only have one Secret Base at a time. Head to the south to find an Elixir.
Once done, backtrack then continue west where you'll have to fight the last trainer in the current route. Continue heading west to reach the next area.
Ace Trainer Brooke (Reward: p864)