Thank you both for your comments.
Homeowners does not cover since they were registered with DMV, which is excluded under the policy (motor vehicles that are registered with DMV?). I was surprised on that, but... We did have insurance on them as the riding parks require that you have at least liability coverage. We have a comprehensive rider that gives us market value. The estimate now is that we will be about $4K - $6K short of replacement, with payment after a 30 day wait. The state troopers opined that if we didn't get them back within a few day, we would most likely not want what was recovered. I think that is right. Still...
A neighbor that goes to work real early thinks he say them riding down the road at about 5am. They stalled out one of the quads, and pushed it down the road. He then heard it start up again, and then they were gone.
I hope to replace my son's quad after we get the insurance. I don't think I will be able to also replace mine. At least not for awhile. We'll see.
The monetary loss is bad enough, but the anger that is building is becoming worse. You find yourself asking "why". Even though I know why, it still seems to make no sense.
Again, thanks for your comments. They were much appreciated.