For a first time haunt, advertising is key. I don't know how much you might be spending (which will vary on your area and how efficient you are able to handle and hire a team to build the haunt.) I'd recommend using cheap labor including vollunteers and day laborers from Home Depot to keep labor costs down. Instead, I would pack about 40% of your costs on advertising.
Expect to spend about 100k-150k. It always comes out to be more than expected...because you should have very strict goals to conserve money.