I view Were Rats in the opposite manner to the above, rather than seperate locked rooms they have one tight, squirming, living chamber. No privacy, and hundreds of shrilly squealing were babies. Even if well away from the sewers proper there is an overwhelming stench of urine. Countless thousands of Dire and regular rats haunt the sewers. were rat sorcerers, wizards, and druids all add their critters to the mix.
a 'trophy' room where the bodies of former opponents have been wired back together, and posed, their valuable weapons replaced with far more worn materials. (Though the armor, less useful for the rats, is still on the bodies.)
A corridor of spiked chains and ropes that requires an Escape Artist check to get through - failure results in becoming entangled and in taking damage (with a risk of poison and disease).
A prison/larder, where homeless people are being stored for later consumption in...
Dining room, stinking of rotted flesh, with the whimpering of victims that have not been killed, but rather left to survive as were rats, or be consumed after they die.
Tunnels that even a dwarf would have difficulty passsing through, but in which a were rat running on all fours is perfectly comfortable.
Submerged tunnels, hidden by the murky effluent of the sewers.
Methane pockets, waiting for open flames to ignite the vapors.
A were rat/vampires chambers, possibly sealed so that even in mist form the creature cannot escape. A very hungry creature by now....
The Auld Grump