Back to the cut chain and all...It took the cops about ten minutes to get there. I let them go down the driveway ahead of me. We searched everywhere, but there was no evidence of theft, vandalism, or off road activity. I considered that they may have only wanted to steal the special $300 "cut-proof" chain, but there was an identical chain across the other driveway opening a few feet away that was untouched. They may be planning to come back. I just don't know.
So, withasmittenkitten 's help, I located the nearest Home Depot where I went bought some new chain. By the time I got back to the land it was dusk, so I decided to just put the chain on and leave. As I was attaching a no trespassing sign to the chain, a car came down the road toward me. (Note: The road is a dead end. The only exit is the driveway which I had just chained off.) Usually when this happens, I get a exhilarating rush of adrenaline and duck into the bushes to see what the bad guys do. But this time I got totally spooked. I jumped into the truck and was considering ramming them head-on, but before I got it started, they saw the truck and backed off and drove away. I finished putting the sign up and headed home.
EDIT: I realized why I didn't jump into the bushes and hide when the car came down the road. It was because I no longer felt I could hide and quietly call 9-1-1 for help. That stupid 9-1-1 alarm sucks. I called Verizon, and they said they have no way to turn off that feature bug. I'm going to call the manufacturer tomorrow and see if they have a fix.