The south eastern tunnel winds back and forth for quite sometime. The width varies, but for the most part its between five and ten feet wide. There are no traps. Small caverns appear here and there, but none are bigger then a person height deep. Eventually the tunnel splits, one into a large cavern and one just continues on.
The cavern is about as large as an inn and stables. There is stone work around the opening and inside. Noise of shuffling can be heard inside. There is a light source inside, but it is a ways from the opening.
Inside there are riding lizards being taken care of by undead. These undead are smarter then the regular zombie, more like a ghoul, but not needing to eat brains. They will attack anyone who enters and doesn't give them the correct key phrase. Level ghouls for the party.
There is writing carved into the stones around the doorway. This was supposed to be a stables, eventually, for the wizard, (who claims to be the ruler of the world). The stalls are set up more for horses then riding lizards, but clearly the wizard meant to have a large stable full of mounts.