Croatia is a very large country that cannot be seen from a single base (or even two or four...!). You might want to invest in a good guidebook or two to get some sense of which regions you most want to see and then come back with more specific questions. I think you'll find that you have many wonderful options to pursue!

For a start, will you leave from Zagreb? Look at Via Michelin to get an idea of distances.

I'd go down to the coast and look at island hopping. There is a good thread ongoing about these ideas from 2012

Here it is
http://www.fodors.com/community/europe/itinerary-help-sloveniacroatia.cfm

Ditto--will you depart from Zagreb? Let us know when you know if you have 10 or 12 days to work with.

We will have 10 days.Departing the US 6/6, with plans on returning to the states 6/17.
Arrive in Zagreb- 2 nights in Zagreb
Drive from Zagreb to Split ( stop in Plitvice)
Split- 2 night
Hvar-3 nights
Dubrovnik- 3 nights,
Depart from Dubrovnik for US.

Does that sound like enough time in each spot to see the major attractions?
We will probably drive from Zagreb to see the village my ancestors are from.

sounds good to me

Sounds good to me, too!

One minor tweak you might want to consider would be to add a night in Plitvice. One can spend as little as an hour or two at the lakes, but I think most people opt for 4 to 6 hours. (The park rangers have plans for 2, 4, 6, or 8 hours and will work with you to tailor something to your time frame if those plans don't suit. Or at least they did when I was there.) As I recall, I spent about 6.5 hours there and loved every minute.

It's a beautiful country - enjoy!

You definitely need at least one night at Plitvice. I spent two, and was sorry to leave. You don't need three nights in Dubrovnik.

Dubrovnik is a worthwhile stop but quite small.

> You don't need three nights in Dubrovnik.
> Dubrovnik is a worthwhile stop but quite small.

True - but I don't think one needs 3 nights in Hvar, either! And I found Dubrovnik a better base than Hvar Town. From Dubrovnik, one can take a day trip to Montenegro or Mljet or Ston or...

If the OP adds a night in Plitvice, I would think cutting one from either Hvar or Dubrovnik would be reasonable, depending on their priorities.

hello,
the best is to stay in Zagreb for a day then go to Zadar or some of beautiful islands that surround it.
from there you can go to Split or Trogir for day or two then to Dubrovnik if you need help I can make you all itinerary
For teenagers maybe to stay at some festival arraund Zadar

suggestion
stay in beautiful hotel in Zagreb for one night, hire a car,
2 day go to Island Ugljan near Zadar stay there for 3 day to see kornati national park an to feel the charm of beautiful islands, 4th day arriving to Split it is only 2 hours with a car. Stay in Split in a hotel for next 3 days, after that go to Dubrovnik approximately 4 hour with a car stay 2 day that is enough Dubrovnik is small town then go to Makarska for two or 3 days there the teenagers will be happy from Makarska you can go to Split airport then home. that is an idea