Itinerary for Croatia/Slovenia and Plitvice Park

Looks pretty good. I think you will find most people do recommend the night
in Plitvice as it helps with crowd avoidance.

One option might be to reduce time in Split to add a night in Ljubljana. But it
depends a bit on your arrival and departure times in each place. 2 nights can
be 2 half+ days and a full day, or it can be a full day if you arrive late and leave
early.

With just a quick glance, I would eliminate Rovinj and spread those days throughout your plan. There is nothing in particular shared that could not be accomplished by elsewhere.
End in Zagreb and take bus or train from there.

I was just in Rovijn this summer, and having been there I’m confident you could drop it and not notice the difference. It’s a big detour for a place that is basically a bigger, more resorty Korcula. Istria on the whole doesn’t make a lot of sense if you’re coming up from the Dalmatian Coast. Redistributing those nights is an easy upgrade on the whole itinerary.

First, you definitely want to keep that night in Plitvice to avoid the crowds and get the most out of it. It’s a bit early in the year for swimming. If you were going to Croatia with the intent to swim and relax, I’d add another night in Korcula. In April I might keep it at 2 nights. Adding a night to Dubrovnik and/or Ljubljana would be an easy win. Dubrovnik has a ton of options for day trips, activities and excursions, so 4 nights is not crazy. Ljubljana is one of my favorite places. I’ve stayed 7 night over two trips and hated leaving both times. Right now, 2 nights is not enough time imo.

Opinions on Split are divided. I enjoyed it quite a bit, though I think 2 nights is about right. I should note that Diocletian’s Palace sights sound like an afternoon of sightseeing, but are more like 20min. So again, if you’re not hitting the beaches you don’t necessarily need a ton of time here.

What is not on your itinerary, and would make a logical addition if you dropped Rovinj, is Zagreb. It’s a good waypoint between Plitvice and Ljubljana, you can drop the rental and proceed by bus there, and it’s a lovely underrated city to boot. You could pass through with a few hours of sightseeing, but I’d spend a night or two if possible. I’ll put it this way: while I’m not sure where I’d go on the coast again, I would absolutely make sure I have time in both Zagreb and Ljubljana on my next trip.

I've been to all the places on your itinerary except for Rovinj. I would definitely spend one night in Plitvice so that you can visit the park when it is hopefully the least crowded: late afternoon on arrival day, and first thing in the morning the next day.

I would keep the 3 nights in Split. This way you could visit Hvar for a day, or visit Trogir, and have some time for sightseeing in Split. Split has a wonderful location on the water, the Riva is beautiful, the architecture is beautiful, and wandering around Diocletians Palace is fun. Split is unique with the city built in and through the palace ruins. We hired Maya Benzon, who Rick recommends, for a 2-hour private guided tour of Old Town Split and the palace. We enjoyed the Ethnographic Museum.

Two nights in Ljubljana is fine if you want to keep the itinerary as is.

Because I have read that it takes a long time to travel to Rovinj, I would agree with the other posters who suggest dropping Rovinj and adding those nights to your other destinations, such as Ljubljana. And I like awrzesinski's suggestion of spending a night or two in Zagreb. We loved Zagreb. It's very different from Dubrovnik and Split. And it makes for a nice logical stop between Plitvice and Ljubljana. We took the train from Zagreb to Ljubljana. Very easy train ride, inexpensive, and about 2 hours long.

I have yet to read a review by a person who did a day trip to Plitvice that said they regretted it. I did a day trip, was fine. You are talking about April which is not exactly high season. If you go mid-week I suspect that will help. I arrived at 10:30 and stepped out of the transfer car and bought a ticket and walked in. But i only wanted about 3 hours of the place. If you want to walk for 6 hours i guess the number of people on the trails will increase by the end of your stay. How much? No one knows. If you drive yourself allow time to get lost, find parking, walk from parking, etc. You might look at package day tours. You buy for the transportation and the skip the line arrangements they have. Abandon the "tour" if you like. Now hire a transfer for the onward journey. Or the bus.

Mr E obviously hasn't read my comments on Plitvice. After I returned from my 2015 trip, during which I daytripped to Plitvice from Zagreb, I started warning people about midday conditions in the park and told people I didn't recommend it as a day trip from Zagreb (or Split).

I've been to Plitvice three times; the first two times it was in Yugoslavia and under-visited. I've experienced the park under both very good and dreadful conditions. There's a world of difference.

I don't know how much lighter visitor levels will be at the end of April (early May?) than they were for me in mid-summer 2015. I agree that a mid-week visit might help. Quite a lot of the people in line with me (for a full hour) in 2015 seemed to be speaking Serbo-Croatian.

Thank you all for your input. Using your suggestions, I made the following changes:
I added a night to Dubrovnik, took a night from Split and canceled Rovinj that leaves 5 nights. Will drop the car in Zagreb. Trying to decide if we should spend a night in Zagreb, if so do you have any suggestions for lodging? Also, do you suggest renting a car in Slovenia?

4 nights Dubrovnik
2 nights Korcula
2 nights Split
1 night Plitivice Lakes (rent car in Split)
? Zagreb (return car in Zagreb driving back from Plitvice
? nights Ljubljana (travel from zagreb Flixbus)

For Zagreb, I can recommend the Hotel Jagerhorn. Very centrally located near the main square. Delicious breakfast. And they have a nice courtyard where you can have breakfast.

We took the train from Zagreb to Ljubljana.

We rented a car for a day while in Ljubljana so that we could drive over the mountains to Lake Bled.

Your new itinerary is very close to what my first trip was. I had zero regrets, this is real solid. I would absolutely stay a night in Zagreb, and two would not be crazy. I think it has a full day of sightseeing in it. 4 nights in Ljubljana is also not crazy, and makes a day trip to Bled or elsewhere an easy call. This is kind of a coin toss imo. Renting a car in Slovenia is not a necessity, but if you are interested in seeing one of the caves would be convenient. There’s also good small group tour companies running out of Ljubljana that can do this for you at a reasonable price (see Slovenia Explorer.)

In Zagreb, Hotel Jagerhorn is a nice choice. Superb location and helpful, friendly staff. I’d stick with Flixbus to Ljubljana. The train is not an upgrade and took longer in my experience. The bus station is a quick tram ride from Jelevic square and costs like a nickel. The station itself is easy to understand. Both drop you at Ljubljana’s train station. Had good experiences with multiple rides on Flixbus.

Have you decided what you will do with 4 nights in Dubrovnik?

Mr E, we have a daytrip to Mostar reserved and a Dubrovnik walking tour. Thoughts?

Excellent ideas. Bodnia & Herzegovina (BiH) still has a lot of unspoiled places between the great sights. See if the Mostar trip stops at the Blagaj Tekija Monastery and the Kravica Waterfalls (bring a swim suit). Its a long day with stops but hard not to do at least a drive by. Spend the night in Mostar even. Then it works great. You have enough time in Dubrovnik. For many, done right, this can be the crown of the trip.

https://youtu.be/3i_9oniJtZU?si=U_Eyg9wcySmMmNmx.

https://youtu.be/vZ-OD5Jd-f0?si=mBdRVIsrbcSdnpyR.

Either a tour or a guide. Yes, the guide isn't cheap but this trip is worth it. And cheaper if you hire a guide out of Bosnia & Herzegovina and I might have a suggestion for that. I did these last Spring but I did them on the way to Sarajevo from a place I was fishing in BiH. I know a very good guide for personal walking tours in Dubrovnik too. I've been in Croatia and BiH several times, wonderful trip.