If I was building a haunted woods attraction... The first thing I would have done is visit a haunted attraction set in the woods...
As someone who started out as an actor, and someone currently saving to open a future haunted attraction, the one thing I CAN do is visit as many locations as I can to see what works, what doesn't, how it's done, etc (and for fun of course).
When I ran a woods event, electricity was wired throughout the entire course. Of course you will have to set up air compressors near any animatronics you have in the woods. But you could avoid that but using only actors. Yet you would still need to route electricity extensively for lighting and sound. It really is up to you to decide where and how to use actors or animatronics. That's where the visiting other haunts comes into play, to see what YOU think works best.
People sneaking in...Have your actors have walkie talkies behind the scenes to call the manager if someone is causing trouble. Walk through with a group on occasion to see what's going on. Fences work best, sometimes overnight security, depends what is most feasible for you.
Whatever you do, ensure what you build can withstand the weather, especially wind.