For the first two nights I had to carry him into the house. I placed a board over the door with a brick leaning against it to try and keep him in for the night. Now he just goes in on his own and smashes down the board in the morning when he is ready to come out.
He seems to like it in there. He went in today during a brief thunderstorm. As soon as the storm was over, he was back out "mowing" the grass.