Baldur's Gate Pacifist Run: Riverside Farmland & Wyrm's Crossing

North of the Friendly Arms Inn, you'll find a riverside pastoral area that's home to some fishermen with a dark story behind their current troubles, and an old farmer plagued by huge burrowing creatures called Ankhegs.
The Ankhegs are dangerous even to pacifist challengers who are pretty skilled at running away from foes, because they can launch dangerous gob-like projectiles, and also unexpectedly appear burrow up to attack you from underground.
One tip is that the Ankhegs, despite their huge size, appear to be susceptible to the Sleep spell, and possibly other nonviolent spells. 
However, in addition to using stealth to prevent them from spotting you, you can also avoid them by choosing your route carefully, since they're only found in particular areas: If you follow the road up to where Ajantis is standing a short way north of the southern starting point, you'll just have to make sure none of the bandits lurking on either side see you, but will have enough room to sneak up north of Ajantis to reach the houses of the fishermen, and other places beyond that.

There is a paladin (or strictly speaking a squire on a sort of knight's quest to become a paladin) named Ajantis who is strong and makes a good lawful good ally if you want to bring him with you: He is eager to join anyone on a quest to oppose evil, and his current goal was just to strike at the bandits plageuing the Coast Way. We didn't talk to Ajantis at first, however, because having a third member while evading foes with stealth and magic wasn't ideal at the time (but as far as we know he won't leave if you wait to talk to him later).

The Fishermen
There are three fishermen at the homes you'll find in the northwest: Sonner, Telmen, and Jebadon. 
Sonner appears to be more or less the leader of the group, and will tell you that they are poor men with hard lives, due to their oppression at the hands of the evil water deity Umberlee's priestesses. The priestesses of Umberlee use a golden Bowl of Elemental control to cause flooding and deadly storms if they refuse to pay onerous tributes, and Sonner says that their attacks have already killed one of them, and is ruining the livelihood of all the others by making it impossible to put out in their boats to fish.
Sonner will consequently offer you some gold and a magical weapon if you kill the priestess for them, but you won't have to do that even if you agree to it at first.   
If you head north (most easily by keeping near the river's edge, to avoid Ankhegs), you can travel one map to the north and find yourself at Wyrm's Crossing. (We'll explain first, then return south to cover the other quest available at the riverside farm afterward.)

Wyrm's Crossing & Tenya the Water Priestess

Coming up the road or riverbank from the south, you'll find yourself at the foot of huge stone bridge fording the river and leading right to the gates of Baldur's Gate, but you won't be able to get inside the city yet if you try (since you'd be stopped by Flaming Fist mercenaries who will tell you the Grand Dukes have closed the gates for the time being). 

If you head north along the wooded riverbank, however, you'll find the cottage where the water priestess Tenya lives, and be able to ask her about the fishermen.  We recommend saving your game first for reasons that will become clear:  
Tenya is very emotional and won't be too forthcoming initially. If you talk to her twice (which is the only way to get to a resolution that we know of), she'll attack you briefly after leaping to the conclusion that you're on the side of the fishermen who want to have her murdered, but fortunately you won't be forced to harm her since she'll soon stop: Be careful, however, as you'll only want to do the minimum damage (e.g. by having Imoen throw a dart at her), after which she should stop attacking and tearfully demand to know why you're helping the fishermen. 
(Tenya will also likely cast an entangling spell which looks dramatic, but isn't dangerous even if it lasts after the combat stops.)
By being patient with Tenya, you'll now be able to ask her about her side of the story, and she'll claim that the fishermen kidnapped her mother (a senior water priestess of Umberlee) and tortured her to death to try to learn the secrets of how to use the Bowl of Water Elemental Control.
If you tell Tenya that you'll side with her and go get back the Bowl, you'll now have the option to return to the fishermen and confront them about it.
At this point, the fishermen will admit that they caused the priestess' death, but claim it was an accident: 
Apparently the fishermen tried to fight back against the oppression of the evil Umberlee's water sect by a pact with the equally evil storm deity Talos, after being persuaded to do this by a priest of Talos from Baldur's Gate.
At this point, the option to solve the  quest in Tenya's favor by demanding the return of the bowl will be offered in the dialogue choices. Sonner will then give you the bowl, warning that the two evil storm deities are vengeful sorts when crossed, and go back into their huts. 
Caveat: Here we again warn that it's best to have the "Party AI" turned off, because the fishermen will become "hostile" to you at this point due to their resentment, but won't ever do anything at all to attack you. However,  if Party AI is left on, NPC allies might automatically start attacking them while they're trying to go back inside their huts. (The fishermen will never attack you even if you follow them inside, by the way, but would just walk outside to get away from you.)
Once you have the golden Bowl of Elemental Control from Sonner, you can take it back to Tenya and give it to her, and she'll be very grateful to you and claim she'll repay you when you reach Baldur's Gate. For completing the quest this way, you'll receive an impressive 2500 xp. (The only thing you'll miss is the +1 Flail that Sonner has, unless you dealt even more sharply with the fishermen by also casting Charm on Sonner and pick-pocketing the flail using your rogue/thief's pickpocket skill.)
Alternative method:
While it wouldn't provide as much of the dramatic background history, there is also a quicker and less confrontational alternative offered by our other contributor, who had his solo halfing thief McGibbits run directly up behind Sonner without ever talking to him or the other fishermen at all, and pick-pocketing both the Bowl of Water Elemental Control and the +1 Flail from Sonner without ever beginning fishermen's the dialogue. He then went directly to Wyrm's Crossing, and completed both conversations with Tenya in one trip to give her the Bowl and receive the 2500 xp.

Farmer Brun & The Ankheg Pit:
There is a sad but nonetheless nonviolent quest that you can also complete in the riverside farmland area on the same map as the fishermen, but one which will reward you with about 1500 xp in total (if you make the right choices in dialogues).
To initiate it, visit Farm Brun's farm and you'll learn that his son Nathan disappeared when he was out looking for missing cows, and is now missing. Unfortunately, you won't be able bring about a happy ending.
Note: This quest would probably be safest if you have the ability to cast invisibility on more than one party member, though it can be done without this.
If your current player character and allies have low strength and can't carry an extra 120 pounds, now would probably be a good time to recruit Ajantis nearby (or some other ally of your choice with high strength). Alternately, you could probably also consume a potion of strength.
You'll find the gaping dark hole to the Ankheg's underground cavern in the west between the fishermens' homes and Brun's farm.
When you descend into the inside of the huge cavern, it will look like a labyrinth, but you'll only actually need to keep to the uppermost passages and head east in order to find the hoard of treasure that unfortunately also contains the body of Brun's son (which you'll need to bring back to him to complete the quest). 

If you have invisibility spells, you can use them here, and a thief's hide in shadows skill will also let you infiltrate the burrows without being seen by the ankhegs, if it's strong enough not to fail at a crucial point.
We tested this using stealth, but it would probably also work to enter and use nonlethal spells, or just run past the ankhegs. Ankhegs are capable of inflicting lots of damage with projectile attacks, but less dangerous if you move quickly without stopping to confront them, as long as you have enough healing potions to make sure they don't kill anyone before you can get away.
If you stick to the upper paths only and don't wander into the cavern, you will probably only have to run or sneak past about three ankhegs. 
The main challenge is when you reach the east end and have to grab all the treasure and the body out of the hoard: This is why you'll need a strong fighter to carry the body. If you cast invisibility on the strong ally, he (or whoever is chosen to loot the items out of the hoard) will have to break the spell near an Ankheg a short way to the east, but you can pause the action while you loot the items. (You can also pass items around to other allies even if they're too heavy for the player who takes them to move around with, so if you kept your strong ally invisible and used a thief with solid stealth or a mage with one more invisibility spell to cast, you could pass the items around and then have everyone leave the caves invisible again.)
We tested a few approaches on different player's runs: The ones who were invisible obviously got out effortlessly, but the others also got out of the caves even without the ability to hide from the Ankhegs: One hit Ajantis with a projectile for a lot of damage, but he was tough and lucky enough to survive, and using some healing potions on him was a minor cost in exchange for the treasures in the hoard, which include valuable wands, scrolls, potions, and magic armor and weapons. (Minor caveat: One potion is a cursed antidote.)

Also, one Ankheg that followed the group out of the hoard was immediately rendered unconscious (but unharmed) by the Sleep spell.
When you bring Brun the body and the sad news (preferably approaching from above the farm to avoid the Aknheg a short way below it), you will receive 500 xp. If you then talk to him again and  ask him to accept 100 gold pieces, you'll get an additional 1000 xp and your reputation will increase.

Regarding division of the xp: 
In most if not all cases, you'll be free to ask Ajantis (or whoever you used to carry the body) to temporarily leave and then rejoin the party, if you want all the xp to go to your own character or other allies: He will just stand where he was whenever you asked him to leave, and you can then pass over the body to Brun to get the xp, and then immediately ask Ajantis to rejoin you again afterward.
If this seems cynical and/or too silly for you though, you should find enough pacifist run xp in the longrun to cut Ajantis into his share here.