The guesthouse where Mr. Mangione stayed is a small building converted from the village’s post office into a bare-bones lodge with four rooms. When Mr. Mangione booked online, there was only a room with a bunk bed left, known as the Hunter room, which overlooks cedar-capped mountains and a roaring river, said Juntaro Mihara, the inn’s owner. He spent six days at the guesthouse.

Unlike other guests, Mr. Mihara said, Mr. Mangione left his room completely spotless and took out his own trash.

“If asked who would be the most impressive and tidiest guest ever in my business record, I’ll answer it’s him,” Mr. Mihara said.