Some places I'm hunching in the area. Consider the State Farm Center on football/basketball game day, even if you're rich and powerful you can easily sneak in there and get full protection. Given it's a big campus with active student life I doubt an outdoor location for Masonic rituals is in the cards.
I've also added a photo of a service road leading from the Uni airport to a shed on the golf course, this likely isn't the "spot" but it's a good illustration of how you can easily host these rituals on private land without people from either the airport or the golf club (except for maybe the owner) knowing anything.
A lot of specifically British symbolism, something to consider as well.
