My party Idea and haunted trail

Every year we have people go thru our woods.We have a haunted trail that is all self guided lots of motion detectors and creepy music. Last year everyone had to follow a list of clues to locate all the items on the trail and if you brought them all back I gave people prizes (scratch off tickets, horror dvds, miniature skeletons...) At the end of the trail we have a very deep ravine that my husband built a suspension bridge over. People went thru that trail over and over just to scare each other on the bridge.
This year I added new points of interest on the trail.
There are ghosts that fly along a line and an air canon, a coffin that slams then opens with a ghoul inside, a cemetery and lots of dead bodies. Everyone has a lot of fun in the woods. This year I've created a story about Bob the landscaper that was helping me clear some land and he disappeared. Everyone has to find evidence of Bob and bring it to me. I'm placing business cards from Bob hiding in the woods. At 10pm the party which is all held outside will be called together by a monolog that my husband has prepared and we'll get everyone chanting "Bring back Bob,bring back bob" at that point the trap doors located on the ground will fly open a large grim reaper will pop out including a huge clap of thunder and lights and his scary voice will yell out BOB IS ALL MINE NOW BWHAHAHA!!!!
I'll post my invitation and some picture next week.