If I wanted to be open for the season, I would contact the fire marshall and find out all the codes you need to be in complience with. Spending your time, energy and money only to be closed down can be devestating. The rules and regulations can read like instructions for changing the time on you car radio but written in some unknown language that only the aliens from the planet where lawyers come from understand. Ask a 100 people and you will get a hundred answers, architects and contractors just don't know, for some reason we fall in some twilight zone that makes "normal" people stare at you with a blank look. Seriously start early on meeting the compliance. After you do you will rest much easier at night knowing 1. You will be able to open and stay open and more importantly 2. You have a safe haunt where people will have a great time and go home safe.
One of the things I've discovered over the years is if you go to the fire marshals early with a preliminary set of plans, they will help you work out the compliance issues. Remember, their job is not to close you down but to keep the patrons safe. I have found if you work with them, they will work with you.