Alright, I just went to the tavern, but hunter is not there (or wickedly drunk and not responding to us because we let him down lol).
I will add another screenshot of the forest village (the one you reach with the mushroom teleporter).
Maybe that is how we got to the cave without the proper quest activated.
I think the entrance to the railway was blocked with some big rocks and some NPC was guarding the gate. Well, we killed the poor fella at the doors to try to sneak in. Didn't work (poor guy). The dead body on the floor kept talking to us anyway.
Then we messed up these rocks and walked in over the rails. Was it supposed to work that way? (Now as I think about it, possibly not)
I've got the debug version running with my latest save, but I did not try too much in there. Ready to shoot all the commands, else I will rerun the campaign.