Either would be great, but they’re very different. Croatia is amazing, but looking at your itinerary I think Nice fits better for this trip. The time involved in getting to, from and around Croatia could easily eat up almost your entire 3 days. What did you work out for getting to/from Croatia for your $300??? What are your interests?

I would plan on flying from barcelona to croatia…then a train from there to Prague and continue my trip as planned…that came out to around $300 more than if i just used a eurorail pass to do my entire journey….the more I look into Croatia the more I wanna go, and the more I investigate ways to and from there the harder and more time consuming it seems

Flying to Where in Croatia? Everything I see for Split involves a connection so 5 or 6 hours of flight and connection time plus 2 hours advance check-in plus at least 1 and 1/2 hours getting to/from airports. Some low fare airlines use a “Barcelona” airport that’s nearly a 2 hour bus ride from Barcelona and the 1/2 hour ride from the Split airport usually takes at least an hour as they wait until everyone from 1 or 2 flights has their checked luggage before the bus leaves. Thus you could easily lose a whole day to flying. I would not spend the time/money to visit just Zagreb, although it’s worth a day or two if you have a week to spend in Croatia.

Zagreb to Prague is 14 hours by train. Getting to Zagreb from the Croatian coast adds at least another 6 hours.

If you want to go to Croatia, then go to Croatia, but I wouldn’t recommend it if you have only 3 days including travel time.

I figured in about a day travel time in between each city regardless….I have a total of 5 cities on my roster and a total of 18 days I’ll be in europe ((May 4-21)).

(I’ve also found, from previous euro vacations, that over night trains are a good way to save on a hotel room and also save a “Day” of traveling.)

Basically I was more or less wondering the pluses and minuses to Nice, and most likely Split & Hvar ???? Would it be worth the plane and ferry time to travel to Crotia ???? I have never been to either place before

Sure, Split/Hvar is doable, but if you are leaving out of Barcelona, I’d probably stick with the southeast coast of France for the next leg of your trip. It’s just a more fluid journey that way.
The coastline between Barcelona and Nice has much to offer.