I know it's been a little while since I put up anything about this, but I'm still working on it. My current dilemma is that I seem to be stuck on the "what" of the whole thing.
My general idea progression for things that I've written before (or idea refinement progression in the cases where the entire story popped into my head at once) tends to be theme/moral, then events, then characters, and setting last...almost as an afterthought, honestly. What I've gathered so far on this was an idea that I loved that has sprouted into a very detailed setting that I'm utterly fascinated with, and an inkling of one or two of the characters involved. I'm almost completely missing events.
Now there are a lot of events that pertain to the story, but they're really more part of the setting than they are the actual story...more of a history of my world. I guess that's one of the inherent difficulties in doing something about time travel: the history and the actual story cross over more than one would expect.
I need an antagonist, I need an event, or a chain of events. I need to find out where this goes...the setting is enough to keep me entertained, but not quite enough to write about.
I'm definitely still working on it though, and the route is definitely there...I just can't quite read the map yet.