Just follow the path to the docks (of Tarant). Keep walking along the shoreline. You will see a small guard station then go in. You'll find your way. It's somewhere near the wise woman's cart.
The dwarf guarding the old sewer entrance won't let me enter it. Is there a quest that leads me there or another way to convince him, except of brutal violence? X
Hm, may be an easy way to get what you want but I practice that roleplaying thing and I also try to achieve some moral goals. At the moment my char is of lawful/good alignment! I'll try your way the next time I start over! X