As I did last year, I'll begin posting a provisional route.
DISCLAIMER: It's still too early to trust any of these stages. Pleas do not rely too much on them.
The more stars a stage has, the more likely it is.

*: Wild guess
**: Sound guess
***: Weak/Old Rumour
****: Strong/Recent Rumour
*****: Almost Sure
1 Napoli - Napoli [flat] ****
2 Ischia TTT ****
3 ??? - ???
4 ??? - ???
5 ??? - ???
6 ??? - ???
REST (huge transfer to Firenze)
7 Firenze - Firenze [Worlds test] ****
8 Firenze - Montecopiolo [Mountain] ***
9 ??? - Parma [flat] **
10 Parma - Vicenza [flat] ****
11 Vicenza ITT ****
12 Vicenza(?) - Vajont [hilly] ****
13 Cordenons - Malghe Del Montasio [MTF] ****
14 Cave Del Predil - Bad Kleinkirchheim [MTF] ***
15 Lienz? - Val Senales [MTF] ***
16 ??? - Gavia [MTF] ***
REST
17 ??? - Nivolet [MTF] ***
18 Ivrea - Susa [flat] *
19 Bardonecchia - Galibier [MTF] ****
20 ??? - Sestriere [MTF] *
21 Milano ITT **
NOTE: There are WAY too many MTFs. Especially in the second week, some of them will certainly be dropped. In order to keep the Austrian stage I had to put the Gavia stage (supposedly queen stage) on a Monday... very unlikely.