“Country Roads,” try not to laugh, or wink knowingly or clap a little too hard, because by the time he gets to “West Virginia, mountain mama,” you’re going to be singing along, and by the time he’s done, you might understand why a seventy-seven-year-old guy from a tiny island in the Taiwan Strait who’s been in a foreign country for two-thirds of his life can nail a song, note perfect, about wanting to go home.