You'll need to make your way to Nettle's Crossing at some point early in Chapter 1 for preventative reasons, as after a day or so of roaming the Stolen Lands your protagonist may start having odd dreams. You have options for dealing with the situation the dream puts you in, but they all end the same way... with a summon to Shrike River. This summons carries coercion with it, as your protagonist will not recover spells or rid themselves of fatigue or exhaustion when this dream occurs. Might as well go see to the cause as soon as possible, even if that's before you actually have such a dream. Having this dream - or completing the errand you'll find below - will start the quest Riverbed Nightmare.
From Two-Rivers Crossing (or from the node south of Fangberry Cave, if you prefer) travel southeast to reach Shrike River, which you then need merely follow southwest to reach Nettle's Crossing.
Note: If you go northeast from the empty node along Shrike River you'll find the Old Outpost. This is a resource node, as mentioned in the notes at the end of your first visit to Oleg's Trading Post. There's not much you can do with it now, but it may be worth visiting later.
Enter Nettle's Crossing and follow the road southeast until it forks at a sign. Further southeast you'll find a collapsed bridge, limiting your exploration in that direction, but should you follow the cliffs to the west, you may spot [Perception 6] a pile of rocks which conceal an Ancient Rostlandic Coin.
Since the path southeast terminates in a collapsed rope bridge, turn down a trail to the northeast and enter a burned-down house north of the road. With a high enough Perception skill score you can spot [Perception 20] a hidden item you can loot for a scroll, potions, and sellable loot.
Leave the burned-out husk of a house and continue southeast to approach the shore, where a drowned corpse will pull itself out of the water to confront you. Ask the corpse who it was and how it died to recall a vision similar to the dreams you may have had. In any case, the corpse was slain by the Stag Lord, and wants vengeance... vengeance that's beyond its power to acquire. Agree to avenge the corpse - it's the only way to get the dreams to stop - and it'll offer up the spear it still carries should you come back successful. Attacking will only temporarily buy you a reprieve from the visions, so even evil characters are subject to the corpse's irrepressible wishes.
With that, you're free to exit the area and continue exploring. If your party is getting tired, don't be afraid to rest, but generally you should let the stock of your healing spells determine when you rest. A little fatigue never hurt anybody, and if it did, you've got healing magics! Seriously, though, if you need to recover, don't be shy about heading back to Oleg's Trading Post. Assuming you don't - and some fatigue doesn't deter you - feel free to continue this expedition uninterrupted. The next area you should consider exploring is the Waterlogged Lowland.