I decided to leave Rusty at home for a few hours and see what happens. Our neighbor was on dog watch to see if he barked, and I moved as many vulnerable things as I could to avoid getting them torn and off I went. First he tore out the dog door panel.
My wife got a text from Brian with a picture of Rusty sitting composed in the driveway, paws crossed watching the world go by- "Is this your dog?" I was stunned. How the hell did he get out? The house was closed the gate was in place at the top of the stairs when I left and now he was outside. Brian apparently took him back in but that did no good at all.
He was in his new favorite spot and came running out when my wife got home. So the moral of the story is trust the dog. I don't know what else to do. He didn't wreck the house or bark or shit in the neighbors' yard. He just sat outside glad to belong and have a home. Luckily I live on a quiet dead end and apart from my asshole snowbird neighbors who bitch and moan and complain about everything and everyone it's a street without drama so Rusty will likely get to see little action. But if he's happy and relaxed I am too.