Dungeon Keeper 2 Walkthrough: Sweetwater = 'Rout / Beseiged': 6
This is an interesting one. You can choose the front or back assault. For the front (Besieged), use tons of bridges to get everywhere, and grab the gold to the NW. Build tons of traps around you, cross-linked. Traps are the key. You have no portal, you must protect every fighter you have and get tons of skeletons to help out. Dig around both long trails in the rock, and you're pretty set.
The back (rout) is harder. There are two items to the NW - dig everywhere you can, but leave walls for your defense! You need tons of traps in this one too. Follow the diggable paths to find items. With patience and diligence you can win this one as well.
Dungeon Keeper 2 Walkthough Index