Ok, so everyone has given great advice BUT here's some important stuff to note as well.
1) business plan. How much money can you put into it and how much do you need to do it right? Where will the funds come from and where specifically would you like to house your attraction.
2) ZONING. This is FIRST. Make sure the space you choose is or can be zoned appropriately, keep in mind parking and the surrounding community. Once you get zoning approved you can move on to building and fire.
3) this will go back to step one, are you a charity or a business? An if you are a charity, do not forget it is still a business, it takes money to make money and you must make money to be able to donate money, don't overspend and make sure your market is right for a haunt (maybe thats why there's none near you?) Your market has to be able to support the business. Yes some haunts are OUT there, but they do everything else right and know how to get people to show up.
I wish you the best of luck and please keep us all posted so we can help and pay you on the back when it's all said and done! Good luck pal!