Anyway, as a standalone adventure, The Wife and I found it incredibly easy. It's in standard "turn tiles over until you find X and then escape" format, with a twist in that a Young Vampire appears after the heroes use their first healing surge. Well, we never had to use a healing surge, and found the Sunsword and escaped with little difficulty. The end.
We've now completed all the official adventures for Castle Ravenloft and I think it was a good investment; we got several hours of entertainment out of it, and I can swipe the miniatures to use during traditional D&D sessions. We've had Wrath of Arshadalon on the shelf for a while, and we're looking forward to cracking it open.