I've been wrestling with this piece for a few months now, probably closer to a year, and I can't seem to progress, only write in circles.
In the meantime, I've been neglecting some other stories I wanted to work with, stories that use - gasp! - dialogue.
I feel that right now, my persistence is working against this piece. Perhaps I'm just not ready for this play yet, and I need time to work on other things first. Rather than force the play through (which results in the play feeling forced), I'm going to set it aside and come back to it later, when there's something I feel compelled to write with it. Then at least I'll be working with something real instead of something I squeezed from my brain out of sheer determination.
So don't be surprised if the next bit of writing is a bit different.