Another way just occurred to me, though this is much easier to do solo or in a duo than with a band. Listen to the later albums of Martin Carthy. On some arrangements - his album 'Right of Passage' has some good examples - the rhythm is very free, with the guitar picking out the melody and passing notes or a counter melody. The idea is that the instruments do not drive the tune, the voice does, just as it would do in free unaccompanied singing. I used to play guitar for a singer and I often played for her in this style. You have to be on your toes and follow exactly what the singer does, but it creates a greater sense of artistic lisence, I think. And it means that between verses there need not be much, if anything, just as there wouldn't be anything with unaccompanied singing.

On the point of having things written down I can't help, as I play more or less entirely by ear. And anyhow I'd recommend avoiding other people's arrangements. The audience probably know how others do it: why sell yourself short by repeating what others do?