That's really funny. I was just thinking about that song that Goose sings driving the pickup. I always thought it was an interesting little moment in the movie (strikes me as one of those fun "actor choices" that happened on set. Now I want to know even more about it...
I used to play my old banjo and lay upon my knee. But now the strings are broken down and no more use to me. I took it to the mending shop to see what he could do. He said just string that broken (?) thats no more use to you.
I speak a little drunken Australian so I translated what she was singing, however, I did find this that you may want to take a look at. Maybe she forgot the proper words.