We were successful at squeezing in more fights than usual.
First, there was a fight with a bunch of undead foes they'd fought before: a vampire gargoyle named Skrall, a vampire harpy named Svetlana, and the dread wraith Sithyl. They had a semi-clever scheme: the harpy would use her captivating voice to lure one of the PCs up through the trapdoor in the ceiling, the gargoyle would slam shut the trapdoor, and then they would pick on the isolated PC.
It didn't work quite so well. They put wax in their ears before entering the castle, except for Liandra, who relied on her awesome Will save. But Turok did take the bait to go up through the trap door. When Skrall slammed the door shut, Turok turned and used Power Attack extremely well, nearly breaking through the iron slab in one round.
Turok did succumb to Svetlana's vampiric domination, but he broke free when he was commanded to attack the other PCs.
Liandra managed to use her new sunbeam spell to good effect, blasting Svetlana into ashes before she could do anything else. She also used it later in the fight to damage Sithyl and dust Skrall.
At about the same time, Skrall summoned Sithyl forward to take his revenge on the PCs.
Skrall, by the way, was again almost entirely useless as a combatant. I think he may have managed to hit Kyle once with a gore attack, but he never managed to make contact with his level drain.
I managed to use the dread wraith's Spring Attack and reach to good effect--both Kyle and Liandra ended up losing a lot of Con to his draining touch, and finding their maximum hit points in the low teens--far too close for comfort. And it made it very hard for the PCs to damage him in return, because he could put walls between himself and the PCs after he was done attacking. Nasty stuff.
The PCs finally defeated him by hanging out in the middle of a big room and using readied partial charges. (I've since concluded that a close reading of the rules indicates that you can't ready a partial charge. This matches my intuition better, but I don't regret the outcome of the fight.)
The next fight was a dragonbone golem, from Draconomicon.
The PCs opened a door (finding and defusing a trap first--yay Kyle) to discover an immense skeleton of a dragon, inlaid with runes. As they tried magical attacks, the spells failed completely, and the runes glowed with twisted inverses of familiar magic runes.
But the PCs found a very good alternate strategy--Liandra summoned a Huge earth elemental and then a large Earth Elemental, and the elementals and Turok were able to pound the golem to bits pretty quickly.
(As written, the dragonbone golem was size Large and CR 12; I'd given it 4 HD and boosted it to size Huge and called it CR 14. I'm not sure it really counted as CR 14--a Huge skeletal dragon with hard-to-penetrate SR and more hit points might have been CR 8 or so.)
Kevin asked, "Why was this here? Just a random trap?" But I had some exposition for why it was there: with Seamus' help, they penetrated the secret page that was hiding the coded text in which Melisande had stored part of her memory (to keep it secret from Garrett's command over her). I got to give a speech I'd been preparing for a while, in which Melisande declared her intentions to not let things rest when Agondre dies, but to replace Agondre with "a new dragon of metal and bone," and reverse Garrett's dominion over her with her command over the new dragon.
So, I was quite satisfied with the session. We managed to pack more fighting than usual into the session as I'd hoped. My tactics were fairly good. My descriptions were also pretty good (at least occasionally)--I felt particularly pleased with my description of Liandra seeing Turok's eyes through the gaps in the trapdoor and realizing that he was dominated.
Now I really must send the players the results of their looting of the vampire's castle.