The notes here are based on the version of the alpha release on the website as of 11 May. It looks like a bunch of the suggestions in the 27 April comments aren't done yet, so I don't know if I was looking at the most recent version (it says 7may10 on the website link).
It's time to do this with Diane, to get some feed-back from her. I think the best thing to do at this point is to be with her when you give the initial demo. Then if she's willing, she can play around with it some more on her own. For the self-guided part, you need to update the howToRunDemo to be consistent with the latest UI.
As a demo starting point, I think it would be very helpful to have a 'File->New' dialog available. I think this is the place that someone like Diane will look first to start things off. The Open and Save items don't need to work. See this page for the contents of the File New dialog.