Marvellous to pick up this thread after all these years and see how people have interpreted it. I have listened to most of the versions mentioned here over these years and depending who was singing it you can draw different conclusions. It remains one of the most poignant songs I have ever heard. I said all those years ago that I heard it first by The Everly Brothers who did a couple written by KK. Breakdown is another excellent version. I still listen to both versions of Casey by them and think the first one was the best but it was done in two takes and then discarded as they had no idea what was going on. They were pretty well washed up then and faffing around with no idea what to do next. Loved their stuff even so but their reunion years were pretty bland even though I saw them a few times. Went on Emmy Lou's trip for many years. A fine artist right through the late 70s/early 80s.
Nice to see that the song meant something to many. Not many I have heard in my life keep me guessing. I am in my 70s now. Country music offered a lot for many years but not any more. Keep searching.