Dear Figbar,
If you find the lyrics to Grandpa's Billygoat, you could post them on this thread. They gently, slowly, but eventually will find themselves in the Digitrad Database mentioned in the upper right hand corner of this thread. It is a database of thousands of folk and folk-related songs. Some have lyrics and tunes and some are lyrics only.
Good luck in finding the song which you seek.
Roger in Baltimore