So I played through it this evening, noting a few copy-errors and the like for an update, but further, I will edit a couple of the encounters.
I had 3 players and after some wackiness involving being filmed for an upcoming Channel 4 documentary about the makers of the computer game Elite (The guys who did it went to Cambridge and met through roleplaying, were inspired by the open-endedness of it, etc.) we got down to business. For some reason they didn't choose either of the healing-capable classes (Cleric, Paladin) and the party consisted of the Fighter, Wizard and Ranger. I fudged my way through explaining the rules (not actually knowing everything about opportunity attacks was a pain for instance) and we had great fun!
The first encounter, a warm-up was nice and easy, as expected. The second a little harder, particularly when the Tiefling Wizard realised he could set fire to the flour clouds and take hardly any damage from it. The extra concealment was a minor effect but made the fight really fun. It was perhaps a little overpowered, one person went down, but they still won with ease. I'll probably drop some of the minions to clear space.
The third encounter went quite awry, alas. Whilst the tactics were sound, I had to fudge the slinger's ammo to one unusual pot each (else they seem way better than the archers!). I think I played the archers wrongly too, removing 5 from their normal shortbow attack when they got scared, whereas perhaps their base is +9 and they have +14 until scared. The Fighter was excellent here, ramming people off of the ledge for falling damage all the time. The Ranger suffered by teleporting up to the ledge immediately and triggering the entry of the priest and his minions. He went down and later died. The Wizard never used his daily sleep which didn't help and also went down then died. The Fighter though finished everyone off and won through.
The two dead players came back as the Paladin and Cleric. The undead fight was very tough until they realised they could pin down the artillery. They won with severe damage so I think with 4-6 players this would be a standard encounter. Finally, the hobgoblins totally pwned them. Hitting consistently, high AC and there was very little they could do so outnumbered. Even with more players I think this would have been tough so I'm probably going to tone it down a little.
So, version 2 will be out sometime tomorrow! Thanks for all the comments so far. Like many of you, it was one of the first 3E adventures I ran and it had a certain charm. The sheer number of available kobolds from DDXP made it a must-convert!