"Ciri's little room was a faithful replica of the witchers' quarters. It was, like theirs, devoid of almost all fittings and furniture. There was practically nothing there beside a few planks nailed together to form a bed, a stool and a trunk. Witchers decorated the walls and doors of their quarters with the skins of animals they killed when hunting — stags, lynx, wolves and even wolverines. On the door of Ciri's little room, however, hung the skin of an enormous rat with a hideous scaly tail. Triss fought back her desire to tear the stinking abomination down and throw it out of the window."
- - pg.65, Blood of Elves (UK edition)
For a while now, Kaer Morhen has been an occasional home to a handful of witchers, none of whom bother with the fortress interior. They occupy only a few rooms — the wind occupies the rest. The kitchen is the most important chamber at Kaer Morhen. It is there that the witchers prepare their meals and gather in the evenings to warm their bones by the fire. On especially dreary winter nights, they might also indulge in drinking White Gull, a mildly hallucinogenic potion.
The witchers hardly fret about Kaer Morhen's declining condition. The few left know all too well that they are members of a disappearing caste and rebuilding the fortress would make little sense. Holes and rubble litter the interior — signs of the riot and the passage of time. In the game's Prologue, Geralt can move about Kaer Morhen relatively freely, finding signs of the past glory of the witchers' stronghold and home. Its vast size is revealed as one ventures through its labyrinth of stairwells, corridors and levels.
Kaer Morhen's residents occupy few of its chambers and care little for comfort. This is a witcher's domain. Most of the furniture is rotting while animal hides and weapons are the only decorative accents. Several other chambers are located on the level the witchers still use, and each is furnished differently. These spaces include an evening hall, library and armoury. The names are outdated as the rooms no longer fulfil their functions. The sorceress Triss Merigold occupies by far the most lavish chamber, the only one to contain a solid bed and a few comforts.
The space above Kaer Morhen's gate was designed for its defenders, thus the presence of siege cauldrons and oriels with cruciform openings. Barrels that once contained provisions and ammunition for the garrison now lie smashed, littering the floor. A catapult projectile has knocked a large hole in the chamber wall.
Concept art and drawings of the Kaer Morhen interior: