Is there a keyboard shortcut to close the edit window in Calendar (and retain changes)? In Calendar 6 (mountain lion) when I use command E to bring up an edit window after I make changes I haven't been able to find a keyboard short cut to close that window and keep whatever info I've entered or changed.

I've searched quite a bit on this question. I've seen using Esc suggested, but that cancels the info/changes. I think that may have worked for older versions of (iCal).
As far as I'm aware, there is no single keyboard shortcut to do this.  What you can do is this; after completing your edit, hit "Command E" followed by the space bar.  Command E will collapse the edit window and the space bar will dismiss the info box while preserving your edits.