By popular request, I finally have gotten around to recording a couple of video walkthoughs of a couple of the tools. Certainly not polished and produced, but should give you a good understanding of these two tools:
Walkthough of the Historical U.S. Counties map tool:
Walkthrough of the Historical U.S. Counties chrome extension:
Be easy on me please, as its my first foray into doing a screencapture walkthrough for youtube :)
I hope these are helpful!