So, recapping a bit.
We have 3 stages in Sardinia, none of which is a TT, making me think there's a very good chance the last stage will be a ITT (Venice?).
After the first transfer they'll go to Sicily. 1 stage I would say, but 2 is also possible. One of them will finish in Messina almost surely.
They'll go north, climb the Terminillo on stage 8 or 9. After the first weekend, one or two stages on the Appennines.
After those, I have no clue. Stage 15 should finish in Bergamo, and stage 16 should finish on the Stelvio. That's pretty much it. Before and after that, I've heard so many rumours I can't do it anymore
In the west, Oropa seems to be 99% in, and there are rumours about 1 or even 2 stages in the Aosta valley. The candidates would be Cervinia (or thereabouts) and Courmayeur (this would be a wet dream of mine). On the east, Piancavallo and Pordoi are also basically sure, but there could be an additional mountain stages. I've heard about Valgardena, Tre Cime and even Kronplatz, although I would ignore the latter. About TTs, there have been rumours about ITT in Franciacorta and in Piemonte. As for the finish, some people say Rome, some say Milan, some say Venice.
So yeah, *** this ***.