Works for me, but I'm crazy.
Here's a start on nights.
Now people can tweak the trip
No place in Dubrovnik is too far from the Buza Bar!!!!

Vienna - 4
Dubrovnik - 3
Trogir/Split - 2
Plitvice - 1 (Slivovitz baby!)
Rovinj - 3
Go to one of the caves on the way to Bled
Bled (kreman rezina)/Lake Bohinj/Vintgar Gorge - 3
Ljubljana - 2
Zagreb - 2
Budapest - 3
Prague - 4
Vienna - 2

I almost forgot, as long as you have a month, when you are in Prague, make sure you go down to Cesky Krumlov and spend a day or two. Have dinner down in the cave.

Thanks maitaitom, I also forgot to say we have scheduled a night at Cesky Krumlov and the rest sounds good especially the krema rezina - will certainly have one of those. Slivovitz? Well, I think you deserve to keep that honor all to yourself! Maybe a drop or two of something a little less potent for a less adventurous soul like me!

Joode, we did a similar trip about three years ago - loved driving through Croatia. We started off in Milan and drove to Lake Bled which was magical. Make sure you visit the castle there - and drive to Bohinj. We didn't stay there as we had 2 nights in Bled and drove to Ljubjlana where we stayed near the Old Town and walked everywhere. The market - both covered and open - is well worth a visit.

Then we drove to Plitvice for 2 nights and stayed at Hotel Jezera which is on one of the upper lakes but it is within the park and so we felt we could maximise our time there. It is a huge hotel but the benefit was being right where we wanted to be. The park is beautiful with a number of trails. The entire lake circuit takes 6 hours but you can go along at your own pace and the park ticket entitles you to use the ferries and the park bus if you get tired of walking!
I believe there is private accommodation in the nearby towns and villages.

Trogir is a four hour drive from Plitvice and we stayed at Vila Sikaa which is a small, family run hotel and is very conveniently located. I would definitely stay there again - go to http://www.vila-sikaa-r.com/ We opted to stay in Trogir rather than Split as it is much smaller and a charming place with a labyrinth of narrow cobbled streets and a romanesque cathedral built in 1213. Some great restaurants too!

We also drove the coast of Croatia but we wanted to see some islands as well so we put the car on the ferry and went across to Hvar. We stayed at a B&B in Stari Grad and it was lovely as we got to know the family and had a good feel for the island. We were glad to have the car as we explored every inch! There are lots of B&B's and private accommodation - one site is http://www.hvar-croatia.com/ -

A restaurant we can highly recommend in Dubrovnik is Labirint - it is on a terrace overlooking the water and the the food is sensational especially the black ink squid!

Can't comment on the car hire - we leased a car through Eurodrive which has offices in Australia so it was easy for us to do locally and cheaper than the hire cars. You have to have the car for a minimum of 17 days (I think that's the number).

Have a great trip!

Tropical_Gal, many thanks for tips on accommodation and restaurants. The Villa Sikaa looks good. That is what I love about this site because of the benefit of getting info from those who have gone before! I have used it to plan other trips and each time have had really great help as well as great entertainment when reading about various travel experiences. I haven't submitted a trip report myself but maybe I should give it a go this time.

We loved Pula and Split. We visited Lipica in Slovenia to see the lipizzaner stallions. We loved Croatia - rented a car and drove all over. You'll love it.

I personally loved Budapest, so I would be inclined to take a night away from Rovinj and add it to Budapest. Rovinj is lovely as well, but much much smaller than huge Budapest. Also Budapest might be a nice contrast to the smaller towns of Croatia/Slovenia.

Another vote for a stay in Trogir, it really is a lovely contrast to the other larger cities on your schedule. We booked House Ivancic, which is right in the center of the old town. The studio apt. with balcony was very economical and worked well for us, however, you probably know that an apartment stay is a completely different experience than a hotel.

We had originally planned two nights in Plitvice, but found that one worked well with our schedule (and the weather conditions). If you leave Trogir early, and can get to Plitvice quickly, you could spend most of the afternoon in the park. If you want more time in the park, you could even spend part of the next morning, and still make it to Rovinj in the afternoon.

Eluckhart's suggestion to reduce your Rovinj stay might work, but remember that your first day will be spent mostly on travel between Plitvice and Rovinj. With a two night stay in Rovinj, you will have only one day to enjoy the area before leaving the day after. Perhaps you could cut time from Vienna for Budapest instead, since you will have spent more time there at the start of your trip.

I like Tom's schedule a lot, with the exception that it doesn't get you up the Peljesak (sp?) peninsula or to an island. That really is a beautiful drive, even in April. Could you take a day out of Prague and put it on one of the islands instead? Both of these suggestions depend on whether you are a "city" mouse or a "country" mouse, because both the peninsula and Istria are definitely country.

Isn't it amazing how fast a month can fly when you are planning? This sounds like a fantastic trip!

--Annie

Thanks so much for all your suggestions. We probably lean to being country mice rather than the city types but hesitate to take the time out of Prague as have heard such wonderful things about it.
OK, we are locked into 4 nts in Vienna and also 4 nts in Dubrovnik (already booked with deposits paid etc. but the rest is still fluid) so now the following 30 day itinerary is floated??!!
4 nts vienna
4 nts Dubrovnik (maybe day trip to Mljet or Korcula?)
(rental car from this point)
2 nts Trogir plus incl. some sightseeing in Split.
1 nt Plitvice NP
3 nts Rovinj(so as to explore surrounding area)
2 nts (or 1?) Lake Bled/Bohinj?
(hope to visit Varadzin & Samobor before surrendering
rental car in Zagreb)
4 nts Zagreb
(train to Budapest -)
4 nts Budapest
3 nts Prague
1 nt Cesky Krumlov (have to have dinner at ?Katakomby!)
2 Vienna

Now, should I have 2 nts in Vienna at the end of the trip (as we have 4 nts at beginning but will probably be a little jetlagged at the start for a day - 24 hr trip via Dubai from Sydney!) or add an extra night to Prague?

Final question - would you pre-book ALL accommodation or (as it's May) take a chance and book in as we go so we have the option of changing the sequence if the mood takes us??

Advice, suggestions, anything?? very much appreciated.