Thanks for the ideas.
My current reasons for having them not following the goblins is that they (the goblins) deliberately left the town in several different directions, using different routes to return home. This means that they seem to have scattered after the battle, making tracking them harder and possibly meaning they haven't all gone to the same place (the goblins are led by some NPCs with the intelligence and power to formulate and enforce this kind of discipline. It's amazing how a half-fiend boss can do that

)
One other thing that might dissuade the PCs is the condition of at least one of the bodies in the village: said half-fiend is a bard with access to the
song of festering ruin (or festering death ... don't have my BoVD with me)
My copy of the 3.0 PH had a demo of a character creation program on the CD, rather than an adventure. Which is a pity, because the northern reaches of Galiban are actually semi-arctic, and getting colder (not that the PCs know that last bit, yet).
The attackers do indeed need to be goblins - one of the purposes of his session is to set up the fact that an abandoned keep near the Brightstone Mines has been occupied by humanoids, so that next session the PCs can be offered ownership of the keep, in exchange for cleaning it out (which is basically a case of me taking the
Base of Operations adventure from the WotC site and re-stocking it with monsters of my own selection).
However, a pipe of the sewers is definitely a 'fairy tale' style item, so I might well include it, or something like it.