On your way to the final signboard, you can go through the Wistful Fields.
Explore Wistful Fields
As you follow the path, you reach a sign that points to the Paradise Barrens. Just north of the sign, you can battle Yoshiaki the Festival Boy, who has a level 60 Seedot, a level 61 Sudowoodo, and a level 60 Lotad. You get 2440 Pokédollars for winning.
Optional: Southern Wistful Fields
You can optionally go south again to the sign, then keep going south until you are past the hill on the right, then go west. There you can battle Kazuki the Festival Boy, who has a level 62 Mankey. You get 2480 Pokédollars for winning.
Just west of Kazuki the Festival Boy, there is a cave that contains some items, and you can encounter Pawniard inside.
South of the cave, you can find a TM138 Psychic Terrain.
If you keep going west, you can go up the slope on the left to reach a pond in the southwest part of the land of Kitakami. Check on the signboard and you will add a Fly destination to your map at Wisteria Pond.
Southwest of the pond, you can find a TM097 Fly.
East of the pond, there is a hill where you can find a TM007 Protect.
Northeast of Wisteria Pond, there are some hills. On the southwest edge of the hills, you can find a TM168 Solar Beam.
East of that, on the highest part of the hills, there is a Terastal Yanma.
At the north end of these hills, you can find a TM026 Poison Tail.
Continue Exploring Wistful Fields
North of the southwest hills of Wistful Fields, you can battle Yoshiyuki the Poké Maniac, who has a level 63 Tauros and a level 63 Clodsire. You get 3780 Pokédollars for winning.
To the northwest, you can find a TM072 Electro Ball.
Northeast of that, you can battle Mutsumi the Delinquent, who has a level 60 Mightyena and a level 63 Gligar. You get 3024 Pokédollars for winning.
On the grassy hill northeast of Mutsumi the Delinquent, you can find a TM113 Tailwind.
West of that, at the west side of the area, there is a low cliff with a cave in it, where you can find an item and encounter Pawniards.
Northeast of the cave, you can find a TM067 Fire Punch.
East of the TM, you can find TM179 Smack Down.
Northwest of that, there is a Terastal Gurdurr.
North of that, you can find a TM069 Ice Punch.
East of that, you can find TM068 Thunder Punch.
Near that, there is a sign pointing to the Paradise Barrens.