Let;s be fair, you probably just bought it as prequel to the linked Ravenloft adventure ;-) But even by itself it is one of the better event based adventures in the TSR line. Mostly because the road-trip half lends itself to it and you don't have to force players to bite each hoko, as on the grand scheme it doesn't matter for the plot (you could just start at the castle and all that is missing is some loot). The castle itself is quite small in comparison to the run-up, but doesn't constrain the players to much in their exploration, the only letdown the usual NPC fight, but at least the players can ingfluence it.