Out doors, a different checklist.
Look up,during daylight for any half-rotted limbs that a wind could bring down on customers.
Do you know what poison ivy looks like? How about the rest of the noxious weeds that can make someone's next few weeks miserable?
Tree roots, sticks can slide forciably into sandals and lesser footwear causing fairly long-term discomfort and much worse.
(Ban such footwear?) I know of one outdoor haunt that does this. A mere foot-injury can require much time to heal.
Keep the staggering, screaming drunks OUT!
Make groups smaller rather than larger. Have enough employees to watch the number of customers anticipated.
Watch the weather forecasts, weather radar..
Be aware of the local wild animal population, don't let them "Help Out"!
Two nights ago, we heard a very long, loud howl, from just over the cliff from our house late at night that was very non-coyote-like.
I think the rumors of Wolf sightings just might have truth behind them. (A man's illegal "Pet" Wolf escaped a year ago just North of town...)