Anyways, the whole party got captured, except for the gnome ranger who made good use of his Invisibility and ran away. This was a great setup for an escape scene with a skill challenge, which went very, very well. They got to roleplay with Irontooth, found out a few pieces of information, and then slaughtered the only-slightly-reinforced remnants of the kobold army.
I'm really curious about how you handled this. My group is about to go through the same thing, and I'm not quite sure how to run it.