I feel that your story needs a lot more fleshing out. You are in a bit too much of a hurry. Slow down a bit and let Gandalf have a smoke or lets have a closer look at Legolas when he appears or Elrond should sigh (he does that quite a bit apparently).
The plot is good though. A bit tricky with the changes to cannon, I am not sure how readers would respond to this. A lot of fans are very protective of Tolkien's prose - you just have to look at the reactions to the film to see that! Are the changes necessary? Could you invent a few new characters to replace dead / oversea ones? eg: substitute Elladan for Elrond, Eldarion for Boromir? just a thought.
Keep at it!
