Goblin Fort Tips
You can poison the goblins outside by poisoning the booze tube with a simple toxin. You will get rid of several goblins that way, and that will make the battle easier. You will need to do it before entering the fortress to challenge the 3 bosses.
Otherwise, you can use the exit to the underdark though the temple by either solving the moon puzzle or finding the secret valve to open the door. This will take you straight to the temple of Selune.
Finally, there is also another hidden exit to the north of the map, that will take you close to the Mountain Pass exit. Not sure if you need to discover it beforehand to be able to use it as an exit. This will take you to a safe location clear of goblins when leaving that would allow fast travel.