Dylan often combines the concrete with the abstract, seemingly effortlessly switching from one to the other and back. A good example of this is 'Workingman's Blues #2' (Modern Times, 2006), in which he sings both about big shifts in society ("the buying power of the proletariat's gone down/money is getting shallow and weak"
and things going on in his personal life ("now I'm down on my luck and I'm black and blue/gonna give you 'nother chance"
and he brings them together seamlessly.
That's why I don't think any of his songs have only one meaning or interpretation, but they're made up of so many different influences and inspirations. Like 'Sad-Eyed Lady of the Lowlands' and I think maybe Dylan was selling himself short in 'Sara'. Or maybe the idea that he wrote the song for her and her alone best fitted the narrative of 'Sara'?
Of course I think everything Dylan writes is about something that is on his mind. What I meant to say is that I think he uses imagery that doesn't necessarily have to "mean" anything in reference to the real world or his own life. I mean, what is 'Stuck Inside of Mobile with the Memphis Blues Again' about? I've seen deep and meaningful interpretations of 'Desolation Row' and 'Ballad of a Thin Man', both equally surreal and multi-layered songs, but 'Memphis Blues' seems to me like just Dylan having fun with word-play. That doesn't make the song any less impressive or enjoyable to me. I disagree though with critics who have attacked Street-Legal (1978) for saying the lyrics were sometimes/often opaque (especially in 'Changing of the Guards').
Great story about Jackson Browne by the way. I believe he's also referenced in Don McLean's 'American Pie', as the jester who stole the crown from the King (Elvis) and Queen (Janis Joplin?) and wearing a coat he borrowed from James Dean (on the cover of Bringing It All Back Home, 1965).