Lordy, how did I miss this thread? 
Ok, the big thing will be selling the war to the Italian people. OTL the Irredentists were rabid over Trento and Trieste and most considered the hated Austrians the true enemy. That said, as pointed out earlier there's a possibility to sell a war for French irredentist claims plus some Austrian gains. This is possible if Germany pressures AH to release at least the Trentino (as they were willing to OTL; note: NOT including ethnically German South Tyrol/Alto-Adige (to the watershed) as Italy took OTL) and Goriza, though as stated they *might* also be willing to forfeit Trieste and Istria if they can make Fiume a suitable sub.
Who's in charge in Italy is a factor. Giolitti is an avowed neutralist and would be happy to take the Trentino offer as a neutrality buy-out. Sonnino caved to irredentist demands OTL, but he'd be more likely to join the war, even CP.
Ok, the big thing will be selling the war to the Italian people. OTL the Irredentists were rabid over Trento and Trieste and most considered the hated Austrians the true enemy. That said, as pointed out earlier there's a possibility to sell a war for French irredentist claims plus some Austrian gains. This is possible if Germany pressures AH to release at least the Trentino (as they were willing to OTL; note: NOT including ethnically German South Tyrol/Alto-Adige (to the watershed) as Italy took OTL) and Goriza, though as stated they *might* also be willing to forfeit Trieste and Istria if they can make Fiume a suitable sub.
Who's in charge in Italy is a factor. Giolitti is an avowed neutralist and would be happy to take the Trentino offer as a neutrality buy-out. Sonnino caved to irredentist demands OTL, but he'd be more likely to join the war, even CP.