I KNOW I should know the answer to this, but I wanted to make sure because I think I had an OL once playing it wrong and so I'm prone to do so.

This is the level with the ever regenerating Master Sorcerer for a level boss, and its the four large tiles in a square.

Question: This is still four separate rooms, with walls that block LOS correct? I think the last guy I played with was treating it as one giant room and I didn't know enough at the time to question it.

That's how we play them. This is supported by a few other dungeons that have similar setups, but put a door right in the middle. If the edge walls werent there, the doors wouldnt make sense. Therefore we take it that the edge walls are there in all cases. I think The Barracks is the room in which it mattered for our group, 4 rectangle tiles made into one big room. Having that center post area makes some spawns possible.

See dungeon 37, it's got 2 of those tiles side by side, with a door right in the middle. This suggests the walls are there.

-mike