I see a split as a forgone conclusion. It will happen one of two ways. Through an amicable process or through the spillage of a lot of blood. This arguing of the minutiae of this state this, that state that, is kind of worthless at this point IMO because they do not factor into whether a split should be done. They borders of the two nations will be contiguous. That right there tells us roughly what states will lie within each of the two new nations.
The reason the split is inevitable I have already stated some time back. We have a large enough faction within the nation that is unable to accept the consequences of a national election. That's it in a nutshell. We have very many differences but that is the core reason. We have what is termed as irreconcilable differences.
We have many that want to continue to live under capitalism, which made this country the biggest success in the world, a nation where millions still seek to come. We have many that see that system as one of utter failure and seek a Socialist/Communist form of government. One faction wants limited government, one faction wants total control by government. There appears to be no means of reconciliation between the factions. Again, the decision to not accept the results of the election of 2016 says it all.
Nations have split and borders have moved many times before. We won't be blazing a new trail, just an arduous one. But it comes down to making it happen peacefully or making it happen through violent actions. The window of reconciliation has long since closed.
Something is going to happen. Neither side is willing to lose. It couldn't be any clearer.
The link below is pretty much a superficial stating of the situation but does touch on some of the most polarizing of points. The author also diagrams his thinking on the boundaries of the two new nations.
http://thefederalist.com/2018/04/10/time-united-states-divorce-things-get-dangerous/