The real question then is, is the mill [i] actually[/i] on fire? That would make it twice now they aren't burning a building down, the other time being the Temple of Chauntea, and from what I recall, the rest of the town where they only set hay and carts on fire.

I say get an aerial view of it with Torus' raven. If it is on fire as he said, it is a lost cause. If it isn't, then why is it not? That would possibly make it a trap as Parum said, with either the enemy outside it or somewhere on the grounds. If we can find out where, we can ambush them in return. 

As for capturing someone, I have to agree a kobold is unlikely to be helpful. If we see one of the humans, we could just attempt to knock them out while we deal with the rest. We still have rope anyway, so we can bind and gag them once that combat is over, and put them in hiding somewhere while we investigate the rest of the area.