@mcforman,
I've attached an epub and mobi of a sample screenplay. Is the mobi readable on your Kindle?
The problem you will have is that to preserve the formatting there is no line-wrap, hence you may need to read it in landscape at a smaller font-size.
It's a calibre conversion of a manually created HTML file where the TXT output (from step 1 detailed above) was simply copy/pasted into a reusable HTML boilerplate template.
The issue of performing step 1 on a Mac still remains, though. Somehow, I
just knew you were going to be a Mac user