I wouldn't worry about it too much. This is just something I made for fun, if you like it cool, if you don't, that's fine. The quest was designed to be fun for my friends to play, if anyone else can have fun playing, that's a nice bonus! I actually toned down the difficulty a loooooooooot, because I realized I had gotten better at the game by testing it, and it would be impossible for my filthy casual friends to beat it. :/
Anyway, The Crypt, Level 2. There is a staircase hidden under a fairly obviously marked grave in the very top left of the map. It leads to the last few rooms of the dungeon, where you can find the happy singing ghost.
The only thing I'd likely change about the quest if I worked on it more is add in a bunch more stupid cutscenes and secrets like the faerie fight. I had an awful lot more ridiculous faeries I was gonna add, but I had to stop making the quest *eventually*.