There are Italian railpasses ranging anywhere from 3-10 days of rail travel. We can print them in our office at STA Travel.
What are you doing in Croatia? There are some really cool island-hopping trips in Croatia. Actually, there are some very cool tours in Italy with big or small groups that can range from 1-2 weeks, which might really work for you if you want to see a lot in a small amount of time.
Let me know if you would like more info on any of these things!
Jennifer gwu@statravel.com 202-747-9772

Split is amazing and you can do a lot of island hopping from the harbor there, it is a really popular destination for that and there area lot of ferries from there. Look up the different islands and see which one you want to go to. Also, getting out of Split on the train is a bit limited to be sure to know when the train leaves. Sometimes it will say there is a train leaving but in fact you have to take a bus to another train station and i might cost a few extra Euros but its not expensive.