Writing a dissertation on Arthur Miller plays?

I have read both The Crucible and Death of a Salesman. Both of them have great uses of symbols and Miller's stage directions are always pack with good detail that you could write on. The Crucible is a allegory to McCarthyism in the 1950s, and you could write on that. Death of a Salesman explores family dynamics and juxtaposition of time periods. Both would be great to write on and are packed with literary meat. I would advise reading one of them and annotating it for any recurring motifs that show themselves. Hope you do well on your paper.