I ended up running this adventure for no less than 12 hours. Part of the time was due to the initial traveling and combat prior to entering the pyramid and what they discovered while getting closer to their destination. Second came from encounters found within the pyramid. I rolled and chose from what their Adventure Level offered to give them random rooms including the zombie minators and the chimera. They actually parleyed effectively with the chimera to fight with them through the next two encounters including some cultists. The chimera charged ahead after defeating the fiercer foes to become deeper entangled in the labrynth. I had to scale down the dragon head by making it a black dragon for fear of it oblterating the majority of the party. I managed to have the red wizard escape and plan to use him as a stand-in NPC in further adventures.
[5 of 5 Stars!]