If there's any way you can make an indoor maze, or make walls outside using stakes for frames or something, do it. Make black plastic walls, strobes, and good props. Also, drop panels are awesome scares. Basically, it's a plywood sheet, with a window or "panel" cut out of it. It looks like a regular wall, until the actor behind drops the panel, making a slamming noise, scares them and slides it back up. Very scary. This scare is very easy to make. If it's outdoor, you couls support it by driving 1x3 stakes into the ground, and securing them to the panel. Help me out with some DIY links here guys!
"If you fail to plan, plan to fail"