Okay, I'm in chapter 1 and I've done some exploring down the river where the troll is, and found this lovely bandit camp/house. There's some bandits there, as well as a guy they hung from a tree and a camp with dead soldiers.

I killed the bandits, but the house door needs a key. Yet, none of the bandits had a key! Or so I though; looking around to see if I missed looting a body, I suddenly see in the distance the silhouette of a man, I suppose bandit, running off to the left behind a tree.

Aha! I think, and run after the guy... and been running around in circles for at least half an hour in that section now, but the bandit seems to have disappeared. He's nowhere to be seen, not on the ground, not in the trees, can't climb the trees, my medallion doesn't reveal anything but herbs. What gives? Where did the bandit go, where is he hiding, where's the key to the house!?

You get the key to the house during the Troll quest. Dmitri drops it when he dies.

[Spoilerish]

You need to complete the troll trouble quest choosing not to kill the troll to get the key.
Maybe you can get it on the other path as well, dont now about that , never killed it myself.

Well, I didn't kill the troll either, I still have to talk to my acquaintences after agreeing to help him find the murders. But I've got other quests, and I figured I go exploring around a bit. Looking for the second wreck up the river to be precise.

lol!!
[Spoilers]


you wont find it in this chapter.
sorry cldnt help myself from laughing :P

I found it in his lower intestines.

I'd say that it's a pretty safe bet to assume that the elusive bandit is Dmitri.

Btw, I'm now in Chapter 2 and although I got the key, never went back to the bandit house to check it out. Anything worthwhile inside...?

Cheers,
Wolfy

Just a sword.
Not as good as a Jagged Blade, though.

You are wasting time if you are still looking for the wreck as the wreck is in chapter 2, not chapter 1. You can find it somewhere in the gullies.