Last night I got together with the group of friends I've been working on a Descent: Road to Legend campaign with. We were finally able to finish the Rise of the Goblins storyline, which we had failed at last time. **Spoilers ahead.
The first room played out much as it did in the previous session. We cleared out the Goblin Archers, dealt with some Barghests, and moved on. This time when we had to choose which route to take, we picked the door on the right, which turned out much better for us.
There was a river of lava in this room, which we were able to use as a choke point to guard ourselves from the rear. This let us keep moving forward and focus on the objective of the adventure, which was to take out the Goblins.
Eventually we were able to make it to the final encounter. It looked pretty grim for a bit, but ultimately we were victorious. I think the key this time was that we figured out that we didn't have to kill everything. The path to victory lay in keeping pressing forward and not getting distracted by searching for treasure or trying to completely clear a room.
After defeating Splig, the Goblin King, we can were greeted with this message.
So Splig lives to torment us another day. But for now, we beat him.