Welcome to the WK club! Let me know if you find a manual.
I've looked and looked and looked... Have even found several other owners around the world, but have never found a manual. I have a schematic pdf that is fairly helpful. Given the length of the Haunted House manual, I'm thinking there may never have been a WK manual.
Drop me a PM if you have questions. I'm adding an 8-track to mine to get the music and have figured out a couple of ways to do that.