Okay, for three nights now I've hung around at the top of the lighthouse in Seyda Neen waiting for that stupid Elf to come a-sneaking into the swamp after Hrisskar wants to know where the hiding place is.
Fargoth never shows up. Ever.
The next night I skulk as usual at the top of the lighthouse, and use the TFC console command to go 'ghost' and find out what the fool is playing at. He stands around a lot with his torch, walks around a bit and then goes home. The closest he's ever come is to stand by the wall of the customs building, stand there for ages (about three hours in game time) before turning around and going home.
The stump itself is 'you find nothing of use', which I was expecting as Fargoth's got to go there before it'll become a 'valid' chest with stuff in, but the quest is stuck until he does the sneaky thing. Which he doesn't.

#1
I've sadly had the some issue, and, after quite of bit of searching and prodding, found no solution. Until a script is added to Fargoth for him to go and activate the tree stump into a hiding place, we're just screwed. Which is inconvenient, as it is a very easy way for starter characters to make a decent bit of money (decent for a newly created character, that is).
I'd add the script myself, but... one of the things I have no knowledge in is the field of scripting. :(