If I were you I would build your theme and back story now. Get a web page and facebook up and running asap with all the backstorys and info. you can even hand out flyers right now with the website and face book info in it stating its coming soon. I would even get a youtube channel up and start making short videos about the haunt or its history and post links to it on facebook. every bit helps and what you dont have to pay someone else to do helps even more
I'm only doing this to impress 2 people ... The fire marshal and the customer that's it !!!