"The road goes on forever …" It's not always easy to sum up a career - let alone a life's ambition - so succinctly, but those five words from Robert Earl Keen's calling-card anthem just about do it.

You can complete the lyric with the next five words - the ones routinely shouted back at Keen by thousands of fans a night ("and the party never ends!") - just to punctuate the point with a flourish, but it's the part about the journey that gets right to the heart of what makes Keen tick. Some people take up a life of playing music with the goal of someday reaching a destination of fame and fortune; but from the get-go, Keen just wanted to write and sing his own songs, and to keep writing and singing them for as long as possible.