Travel from Croatia/Solvenia to Lake Como?

If you travel north to south in the Slav states, you can fly directly from Dubrovnik to Milan on Easy Jet for pretty cheap. That's what I did last June.

That flight is available only starting July 4th. That would be great if it was!

You have a very ambitious itinerary - if you are planning on stopping in Split on your way from Dubrovnik to Plitvice in one day, it will have to be a very quick stop. Do you have travel days in addition to the days you plan for each stop? If not, you will be traveling a lot and not spending much time anywhere. But to your questions - we spent 6 weeks in Croatia, Slovenia & Vienna in Spring 2010. From Dubrovnik to Split, there are regular buses - trip about 3.5 hrs with a short stop in Bosnia-Herzegovina. We did this trip. Did not go to Plitvice but I believe there are buses there as well. There are no trains in southern part of Croatia. There are ferries but they would be slower and not as frequent as the buses. We rented a car thru Sixt in Split and drove it into Slovenia. Then returned to Croatia and visited a number of the Istra peninsula towns. There was no drop off fee for returning car in a different Croatian town (fee is 200 Euros to drop off in another country). Not all rental companies allow you to drive into other countries so if you use this option, check that out. We did not go to Italy from Rovinj but know there are regular ferries from that Istran town and a number of other towns (Pula, Porec, etc) to Venice. On a prior trip to Europe, we took the train from Venice to Como via Milan. There were a few trains a day. Verona is along the Venice to Milan route and we made a 1 day stopover there. So, I would suggest a mixture of bus, rental car, ferry and train - depending on your location. To get to & around the Istra Peninsula a car is almost a requirement. I have noted this being mentioned on other RS travelers helpline posts.
Happy travels.

You can do it all by public transport, but it takes time. We took the bus from Trogir to Plitvice (it was the early morning bus from Dubrovnick to Zagreb). It was an interesting trip (Plitvice is well worth the effort). You have to be sure that you ask about the bus to Plitvice - the main route to Zagreb doesn't go that way. I don't think I'd try to do Split unless you are renting a car as mentioned in another post. We didn't arrive in Plitvice until very late afternoon (also, if you take the bus - there was a 30 minute stopover shortly before we got to Plitvice - dinner break for the drivers - if you can determine for sure (we didn't figure it out until later that it will be 30 minutes, try to get something to eat - there aren't many options at Plitvice. Plan to stay overnight (Rick's book had some B&Bs (can't remember what they are called in Croatia) so we did that and walked to the lakes. We must have stayed 2 nights - then took a morning bus to Zagreb, then train to Lublijana (stayed overnight), then bus to Lake Bled (which is wonderful - stay at one of Rick's B&Bs. We did rent a car for one day to drive up into the Julian Alps, but otherwise did it all on trains or buses - but it definitely takes extra time. The hostel (double rooms, shared baths) in Lublijana is great (it's in an old jail - walking distance from the train station and easy walking around town). I think it's in Rick's book as well - it's considered one of the best hostels in Europe - quite the interesting place. It might be pretty noisy on weekends. We headed to Hungary from there, so can't help with the Italy piece.

Just a suggestion. From Split, you could take an overnight ferry to Ancona in Italy, and train from there to Milano which is an hour by train from Lake Como. In Ancona, the ferry dock is a short local bus away from the train station.

Depending on the day of the week you're traveling, you may be able to take a ferry from Rovinj to Venice and then train to Lake Como. Rovinj to Venice departs Wed-Fri-Sat at 8:30 am. Here's the link: http://www.find-croatia.com/ferries-croatia/ferry-venice-rovinj.php.