The other day on PBS, they showed a clip of John at the Sydney Opera House after a concert (in 1978.) He was in the audience section (no audience present), talking about the comfort of his guitar. He then sat and played "My Old Guitar". It was a moving performance (fine fingerpicking too.)

P.S.
Seamus,
Your John Denver story warmed my heart and made my day!

Merry Holiday,
Folkie