Need Help with Week 2 Croatian Itinerary

In October, you can for the most part play it by ear. I would actually consider winging it! The driving tour part is very fast-paced, so you could note which places you respond to the most and return to them. The only major omission I see is Plitvice park, which you could stop at on your way back south. Istria is the best place to be in October. The islands are mostly winding down in October, but Hvar and Korcula might be okay.

I have not been to Dubrovnik, but been to Split. Dubrovnik, from I heard, is tiny and isn't a springboard to outlying islands. Split is worth more than 1 night.

Another thing to note: Back in the normal times, I would have suggested Bosnia-Hercegovina, for that's a place on my list for when I get back to the area, but I don't know what border crossing complications you might run into nowadays.
Even without covid, there is a border crossing depending on what route you take to get to Dubrovnik, but I have not traveled that route and cannot advise. Any guidebook will certainly note it. Or, just google "Neum corridor." It is not clear what route you will take as you go north so your trip details might explain it as well.

Livade will take about 5 minutes. Go to Motovun and Grožnjan on your way to Rovinj.

I would add 2 more nights in Zagreb. It's one of my favorite towns. There are 6-7 good museums, and the most interesting is the Museum of Croatian Naive Art, which is done by artists who depict many rural scenes on glass panels. Luminescent. There's a traditional museum as well. If you are there on Saturday, there is a great flea market for inexpensive souveniers. We enjoyed Purger Restaurant, which is a traditional Austria-Hungarian restaurant. There are many bars next to Jelinic Square. Night life is good.. If you enjoy futbol, watching a game outdoors in the bar area is a treat. We also did the "Haunted Zagreb" tour in the twilight, which was a ridiculous hoot. There is also a fine archeological museum. Most people speak some English.

Plitvice lakes Jezira is best done late-afternoon-next day. It can be crowded, but probably not in October. Determine how to get a ticket for 2 days - you may need to stay in an official hotel. We stayed in a sobe (Croatian airbnb). The park is a wonder.

You could then go on to Ljubljana for 3 days. You could take the train from Zagreb, and do Ljubljana on foot - it's a small town. You could take a bus from Zagreb to PLJ, and then back.

Other things to do are Trogir (boat ride from Split) and Sibinic. Split has a fine archeological museum. I'd get a driver to go to Mostar, home of the famous bridge, and to the preserved town of Pocitelj.

I second Paul’s ideas:
Nights 1-2 Zagreb
Nights 3-4 Ljubljana
Nights 5-6 Plitvice
Final night back in Dubrovnik to catch your flight

Or

Nights 1-2 Zagreb
Nights 3-4 Plitvice
Nights 5-6 one of the islands, depending on what’s open
Final night back in Dubrovnik to catch your flight

I like Zagreb too, it's an underrated city! But do check the recent posts here--someone said several museums were still closed from the earthquake.

At that time of year things are winding down along the coast but not closed completely. Zagreb deserves a day or two but be informed most of the museums in the lower town were not open due to earthquake damage. The Ethnographic Museum was open and was fabulous. We didn’t go to the upper town this trip so I don’t know about those museums. You will have to check websites. Our favorite restaurant is Vinodol in Zagreb. veal Schnitzel is not in the menu but they will make it for you, the best. Karlovac is where they make their beer and is a nice little city. Plitvice Lakes is a must see, then try Šibenik, a little more time in Split, and/or Trogir. It was no problem going into Bosnia to visit Mostar. We held up our passports, they didn’t even open them. Waved us right through. The bridge bypassing Bosnia is complete but the entrance/exit roads are not. They should be completed by then so driving to Dubrovnik will be that much easier.

like Zagreb too, it's an underrated city! But do check the recent posts here--someone said several museums were still closed from the earthquake.

OP is traveling in 2022. If the museums are not open by then, that will be concerning.

ha, thanks for that catch Paul--I barely know the day anymore, much less the year.

Thanks everyone for your replies. It helps alot.

Don’t expect those Zagreb museums to be open in 2022. When we were just there 2 weeks ago there was no work being done and it didn’t look like it was going to be starting anytime soon. I was told they are waiting for funds from the EU. Could takes quite awhile. Things never move quickly in Croatia, even on the best of days.

I'm a big fan of Plitvice Lakes National Park and feel as if I'm constantly warning folks not to day-trip there because of the potential for extreme overcrowding. However, I don't think two nights are necessary.

I don’t really understand the nature of the Porsche driving tour as it seems so fast-paced. Is it set in stone or is it changeable?

Assuming you want to keep it exactly what it is, I would consider returning to the Istrian peninsula and staying either in Rovinj or possibly Pula. We stayed in Rovinj for 4 nights and loved it - beautiful town and we visited Pula one day and the hill towns the next (Motovun, Oprtalj, Groznun), though the last town was too much for one day for us. Pula is fantastic for its Roman ruins.

We also spent time in Zadar (loved it) and did a day trip to Trogir from Split. Trogir is also a beautiful and charming town, much smaller than Split and worth spending a day in.

Given the time you have, I wouldn’t return to Zagreb, since many of the museums are not open due to the earthquake damage.