I used it as the basis for this year's Masters and Minions AD&D tournament, "Horde on the Borderlands", in which the players discover that the Keep (qualifier round) & Caves (championship round) are overwhelmed by monsters from our books, each group of whom are at war with one another. The heroes each have their own conflicting agendas, and can make allies or play one side against another once they figure out what's going on.
It's great for this kind of thing, and now that I know how to use a mini-setting, this one is chock full of classic D&D goodness (much more so than T1, which is decidedly lacking in the dungeony, monstery department).
It was a terrible introductory module, though; the fact that the denizens of the Keep lacked names but had combat stats set the development of our players' roleplaying, and our characters' ethics, back by many years. ("This time, let's try taking out the orcs before we go up against the Keep...") And though I can see now that there are hints about how the monsters can be negotiated with, manipulated, given clever tactics, etc., I needed much more to go on when I was 10.