Part 1: Just started

Old Rod (Celanto Town condominiums)

Just started opens 13 areas. There are 21 trainers standing in them. The fights at this checkpoint are Rival Coulter (Chimchar), Rival Coulter (Piplup), Rival Coulter (Turtwig), and 3 more.

Where to go

1. Celanto Town

   Wild: Chimchar Lv —, Piplup Lv —, Turtwig Lv —

2. Reliquia Ruins

   Wild: Tentacool 90% · Lv —, Natu 40% · Lv —, Elgyem 20% · Lv —, Swablu 20% · Lv — +5 more

   Pick up: TM37 Iron Head

3. Celanto Path

   Wild: Zigzagoon 40% · Lv —, Bidoof 20% · Lv —, Taillow 20% · Lv —, Bunnelby 10% · Lv — +2 more

4. Archan Tunnel (Room with the kid)

   Wild: Zubat 40% · Lv —, Roggenrola 20% · Lv —, Whismur 20% · Lv —, Woobat 10% · Lv — +2 more

5. Archan Tunnel (B1F Room with Hiker, Picnicker, Youngster Trainer battles)

   Wild: Binacle 90% · Lv —, Whismur 40% · Lv —, Roggenrola 20% · Lv —, Spinarak 20% · Lv — +6 more

6. Archan Tunnel (1F Exits north of Redwood's house)

   Wild: Zubat 100% · Lv —

7. Archan Tunnel (B2F Room with the Scientist)

   Wild: Whismur 40% · Lv —, Drilbur 20% · Lv —, Zubat 20% · Lv —, Geodude 10% · Lv — +2 more

8. Archan Tunnel (1F Exits to Seros Village)

   Wild: Zubat 40% · Lv —, Roggenrola 20% · Lv —, Woobat 20% · Lv —, Makuhita 10% · Lv — +2 more

9. Archan Tunnel (B1F Floor with no Trainers)

   Wild: Whismur 40% · Lv —, Zubat 28% · Lv —, Scraggy 20% · Lv —, Joltik 10% · Lv — +1 more

10. Seros Path

    Wild: Flabébé 100% · Lv —, Bunnelby 30% · Lv —, Mareep 30% · Lv —, Nidoran♀ 10% · Lv — +4 more

    Trainers: Lass Lanessa Lv 5, Youngster Jenson Lv 5

11. Archan Tunnel

    Trainers: Hiker Quinn Lv 3, Picnicker Louise Lv 3, Hiker Georg Lv 4, Rocker Frederick Lv 4, Ruin Maniac Bob Lv 4, Youngster Cory Lv 4 +4 more

12. Archan Town

    Trainers: ★ Rival Coulter (Chimchar) Lv 5, ★ Rival Coulter (Piplup) Lv 5, ★ Rival Coulter (Turtwig) Lv 5, ★ Elder Knight Eunice Lv 54

13. Seros Gym

    Trainers: Fairy Tale Girl Rose Lv 6, Aroma Girl Courtney Lv 8, Youngster Daz Lv 8, Fairy Tale Girl Hanako Lv 8, ★ Fernando Lv 12

★ Rival Coulter (Chimchar) — Archan Town

1 Pokémon · level cap Lv 5 (every cap) · Rival Coulter (Chimchar)’s own page

	Pokémon	Moves
	Chimchar Lv 5

★ Rival Coulter (Piplup) — Archan Town

1 Pokémon · level cap Lv 5 (every cap) · Rival Coulter (Piplup)’s own page

	Pokémon	Moves
	Piplup Lv 5

★ Rival Coulter (Turtwig) — Archan Town

1 Pokémon · level cap Lv 5 (every cap) · Rival Coulter (Turtwig)’s own page

	Pokémon	Moves
	Turtwig Lv 5

Also fought around here

Everything you can have caught by this checkpoint · Open the interactive guide

It also doesn't say when Rimewood Forest opens up, so it is in no part above; it has its own route page.