Will, you are 7 months ahead of me as I am planning more or less the same trip (from Amsterdam). To get as much driving time in the South I'm thinking of taking an auto-sleeper-train from Holland to Italy (Livorno) cut to the other side of the Italian boot and take a fast ferry from Ancona to Ingoumenitsa (Greece). I'm not so sure about Greece though with its nasty economical situation and all. Would be no fun if their banks run out of money and their ATM's end up dry. I've done the trip to Croatia before and I entered Slovenia from the tip of Italy, at the point where the three countries, Austria, Italy and Slovenia, come together. There is a lovely winding pass across some old border-crossings with remnants of the war between The Austrian Empire and Italy. Further south I hugged the coast through Istrie in Croatia, which is quite touristic in the high season and took a short ferry crossing to the northern tip of the Island of Cres. This Island is stretched a fair way south and the main road is quite scenic and a delight to drive. From the southern tip of the island you can take a ferry to mainland Croatia again and head further south. This will involve some island hopping but the Islands are beautiful and the ferry tariffs used to be fair. I just might take this route on my return trip again. Have a safe trip and let us know how its been! Cheers, Rob.