Well, we know the basic locations of all five gates and have a rough sense of the geography. Most of them are in the wilderness with the exception of the Azure City rift, and the Redmountain and North Pole rifts both seem to be located underground.
....you know, you're right. I might not know exactly how I'd defend a gate in schroedinger's geography, but if I change the question to how to defend a given story gate....hm. I'll give it some thought, this thread is fun!
"Thursdays. I could never get the hang of Thursdays."-Arthur Dent, The Hitchhiker's Guide
"I had a normal day once. It was a Thursday." -Will Bailey, The West Wing