Okay, understand that I haven't run the adventure yet and this is all form one read through of the module.
I thought the premise of the adventure was fine and it seemed like it would work best as a continuation of the adventure from the main book as MerricB has already stated. I will nit pick though that I felt a little cheated by the portion of the adventure that tack place in the capitol of the hobgoblin kingdom. I realize the PC's are only supposed to pass through there, but I felt not detailing a few key places such as a tavern, or a weapon shop were a failing.
If the PC's pass though a civilized placed they will invariably want to look around a little. I know I know. I can always make these little places up and I will if I run it, but in a published adventure I do think that this was a failing to not at least give us some basic sites.
Take it for just my 2 Cp's tossed in on an otherwise interesting looking adventure.
-Ashrum