You need to be able to show them a potential return on their investment. Sponsor's give money, not as a donation, but as an investment. Yes, some businesses sponsor youth sports and the like and do consider it a donation. I have done it for years and have yet to get my first customer from it. 100% loss in terms of money. But it is for a good cause in my opinion. Youare looking for $$$ to start a for profit haunt. Whats in it for them.
All that being said, try local hardware stores, ones you plan to purchase materials from. Local food / pizza places. Try to get a promotion developed that offers cupons to both places. Buy a pizza, get $5 off admission. Buy admission, get $5 off a pizza. Make sure you have hanouts to pass to your customers as tney leave that includes a VERY short thank you letter to any and all sponsers. Also include the associated cupons. Good luck.