I'm running the 3FoE with 5 players: Ftr, Clr, Rog, Barb/Clr & Wiz. They started the adventure approximately midway through 3rd level. We were pretty heavy on the roleplaying in the first adventure, so by the time they got the green worm from Filge's and talked to Allustan, they went straight for the Dourstone mine. With a combination of bribes, fast-talking and bluff they made it into the elevator shaft pretty easily (within the first two hours of play).
So they immediately encounter the two tiefling guards in the dark cathedral. The first holds them off with darkness while the second makes for the door to Hextor's wing. The party cuts him down just as he opens the door, letting loose the skeletons. The single-class cleric blasts all the skeletons with a good turn check, the party advances into the first room and get mobbed by the commoners. The tiefling guards in room 4 follow the same strategy as the initial two - darkness and run for backup. The Beast is loosed and pounds the party pretty well. The only surviving tiefling warns the guards in 6 and runs into the battle temple, drawing his bow. The guards in 6 bar the hall door and run to warn the rest of the complex. The party finishes up the Beast and commoners and charge into the temple to take out the last tiefling (who makes great use of the big statue as cover). As soon as the last party member is inside, Theldrick closes the door behind them, trapping them in. He gets a few rounds to buff up while Garras and Kendra throw spells and the party works on getting up to the balcony. They finally make it up and start pounding on Garras, who's getting great healing support from Kendra. After a fantastic combat, Garras is pulp, the remaining tieflings and zombies are dead/more dead, Kendra manages to stabilize at -8 and Theldrick bites it in the Chapel of Hextor (room 9), surrounded by the party. We were in combat time the whole running battle, which lasted around 2-3 minutes (roughly 26 rounds, IIRC). Needless to say, the party was pretty banged up and spent: spells gone, lots of potions used, etc. They figured out that by leaving the hall door barred and the big battle temple doors closed that they were pretty secure.
I thought about what might happen overnight. I ended up deciding that the commoners in the Hextor wing were responsible for bringing down supplies from the outside world and taking out the trash (that's mentioned somewhere, I think) and that the rest of the complex's inhabitants weren't likely to go outside of their respective wings. For one night at least....
So the party used up a bunch of cure light wand charges, bunked down in the barracks and crashed. They timed it pretty well - they had garnered enough XP to level to 4th during the big battle, so they woke to the "quickening." They healed Kendra enough to wake her (bound of course) and proceeded to question her. They got out of her that the labyrinth mentioned in Theldrick's journal was located past the door to the north before she chewed out her tongue. They party then set out for Vecna's wing.
They're in the middle of the labyrinth now - I expect them to wrap it up at tomorrow's game - and I'm trying to plan ahead for the post-mortem. Assuming that they storm through the remainder of the Vecna temple, I imagine they'll either return to the barracks in Hextor's wing or go back to the surface (it may depend on if they manage to decipher the scroll from Theldrick's desk). So I need to a) figure out if the grimlocks in the the Erythnuul wing will notice anything amiss and b) ensure the party advances on to the grimlock lair without going straight to the Mistmarsh following the clues in the encrypted scroll. Perhaps I can combine these.... A small party of grimlocks have left the caverns to notify Theldrick and the Faceless One that Grallak Kur has had a vision that must be passed on to them.
So, how has your party worked its way through this adventure?