The FindMyiPhone app doesn't provide an IP; instead it displays a dot on a map at the location of the iOS device. Your visitor's story was a fake, and you're very lucky the encounter ended as well as it did.
I too have a long driveway: 1300 feet. Electric gate at the top, which I can't see from the house as it's over the top of a hill. The gate stays closed and locked unless I'm going through it or someone has told me that they're coming and I'm home to receive them. It came with hand held clickers that work like an electric garage door opener, and also has a keypad on the outside of the gate. There's a clicker in each car/truck, and in the tank bag on the motorcycle, so there's no longer any need to get out in bad weather or darkness to open the gate.
Before I put the gate in I had a scary experience when a strange car came down the drive with two people in it. I was in the driveway unloading a truck at the time. It stopped about 100 feet from me and one person got out. He was tall, had dreadlock hair, a brightly colored cape, and was holding what looked like a cigarette in his hand. As he got closer I could see it was hand rolled and smoking. It smelled like dope. He walked up the driveway like he owned the place and introduced himself with a Jamaican accent. It seems he used to grow dope in my new-to-me garage (one bay of which had been walled off and insulated, and provided with 220V power), and wanted to know if I wanted to go into business with him. I let him know I wasn't interested, and that the bay was next on my list for tearing out. I also let him know he wasn't welcome on my property, and asked him to let his "friends" know as well. He slowly turned around and the car left. I didn't have the presence of mind to a) go inside and call the Sheriff, b) get the license number of the car, or c) arm myself when I saw the car approaching in the beginning.
Reading through this thread and thinking more about that incident, I don't think I'll be leaving the gate open any longer, and will instead give whoever is coming a one time combo for the electronic lock. I'm also going to install some additional motion activated flood lights along the drive, and warning devices that will set off a chime inside the house when someone goes through the gate. I'm also looking at installing a few cameras, but the complexity and managing the imagery is somewhat daunting, even though I have twenty some years of IT experience. Now I'll be shopping for a spotlight or two. The ability to blind whoever is on the other end seems like a good safety measure and using the one on my shotgun could be unnecessarily hazardous to their health and my freedom.
The only time I ever had someone knock on my door at night was very late and woke me from a sound sleep. Before I opened the door I had every light on inside and out, and both my wife and I were armed. She stayed inside watching with a phone in her hand while I went out to meet what turned out to be local firemen that had come to investigate a burn pile reported by my troublesome neighbor. Now I think if anything like that happens again I'll call the Sheriff to verify that it is legitimate LEO/fire personnel before going outside. At least that way there will be a record of the incident, even if it turns out to be a false alarm.
It also occurs to me that it would be a good idea to have a talk with some of my other neighbors along the lines of arranging mutual aid. The Sheriff is at least thirty minutes away and we have known bad apples around that I'm sure would take advantage if they knew they could get away with it.