Narshe is in the mountains in the middle of the north part of the world map. There are plenty of useful things to find here.
Back in Narshe
153. Test Rider
Go north, and Lone Wolf will talk to you.
155. Mag Roader/MagRoadr/Magna Roader (brown)
Go west from the entrance of Narshe and check on the wall to open Locke's secret door. Follow the path, then when you are outside again, go west, then go into the door to enter the next part of the caves. Follow the straightforward path through the cave, then when you see a door in the south wall, go through it. Go north and you will find the Moogles' home. Go north and talk to Mog, and he will join you.
Once Mog joins you, check the wall behind where Mog was standing. You will get the Moogle Charm/Molulu's Charm, which prevents all random encounters. But only Mog can equip it. You can use Warp/Teleport or a Warp Stone/Teleport Stone if you want to go out to the Airship and put Mog in your party now.
From where you met Mog, go through the northwest wall and the northwest door, and from there go south, then use the door on the right.
Go south and you will see a chest on the left. If you left this chest alone earlier, it will contain an Elixir. Go east from there, and if you left this chest alone earlier, it will contain a Pod Bracelet/Guard Bracelet. Then go south to leave the cave.
Mog was talking about someone that you can meet in Narshe, but you will probably have to wait until you have leveled up a bit more before you attempt it. If you think that you are ready, read Another New Friend in Narshe.