It took me a while but I think I get it

There's an old Virginian vibraphone, With a calculated gait - Perhaps Gandalf, and old old sounding person (instrament) who walk or does things with thought

And a man who thinks he's Al Capone, With a cumberbund and cape - Aragorn, who thinks her tuff and dresses like a foriegnor

Don't criticize what a vicar would prize in you - don't question what Gandalf/Sarumon

And talk to the man if you feel he needs talking to - Gandalf goes off to talk to Sarumon

And the hobbit on the rocks is crying - Frodo being antsy as always

And the fish upon the docks are dying - Armies/the good people dieing.

There's an orchestra in rococo - The hobbits being a sort of band who has teh air of being opulence, grace, playfulness, and lightness.

and an insulated dwarf - Gimli being suborn as always

And the ships are sinking in the sea, As they sail from the shores - Borimer being sent off on his canno/ dieing

For the grunion in the sand entwining - Aragorn and Awern in love

Don't criticize what a vicar would prize in you
And talk to yourself if you feel you need talking to - listen to one's self

What do you think of it?