Suggestions Please! Honeymoon in Croatia

I've been reading that public transportation is really great in Croatia, so maybe we wouldn't need the car!

I think you have been misinformed about that, at least somewhat.

It depends (very much) on exactly where you want to get to, and how much time you have, but IME, Croatia is one of the countries in Europe that is best done by rented car, at least for large parts of it. Croatia is not much on trains, so with no car, you are either on a bus (not really what most folks dream of for their honeymoon) or, if island hopping, a ferry. If all you're doing is skipping from one island to another, sure, no car needed.

Late May, or June should be warm enough for most outdoor activities, but before the "high season" kicks in (and brings major crowding in places). Early- to mid-June might be ideal.

I would suggest you reconsider that "8-10 nights" constraint. Personally, I don't think it's wise to go all the way to Europe for such a short trip - I think you would find that there's so much more to see, and being right there, it would be heart-breaking to have to leave after so short a time. Yes, I get it about constraints on vacation time, but it costs a lot to get there, you don't have that many chances to go, and it's worth trying to maximize your time there to the extent that you can. Hopefully you can find a way to squeeze out another week or more to extend your trip.

As for where to go...there are lots of choices, but hard to pick just two places. Dubrovnik (everybody goes there, so expect serious crowding) plus one more... (or stay longer if you can, and hit more places). Grab a good travel guide, read the book; skim the tour itineraries and see what interests you most.

And congrats on the nuptials!

Our trip was about 15 years ago, when they had just built their great freeways, and had rented a car in Venice, drove over to Slovenia/Croatia, then turned it in back in Venice.

We didn’t go to Dubrovnik, despite its acclaim, and sounds like its really a destination for mobs now. We also didn’t head out to any of the big islands in the Adriatic - drove to a small one connected to the mainland by a bridge for a day trip. Can’t exactly offer any pampering spots advice for Croatia, either.

Our main stay (besides Zagreb) was in Split, where a Roman Emperor built his massive retirement villa 2,000 years ago. Nice city, and we actually stayed just north of Split, in Solin.

Another place that’s really magical, and sounds like it’s more and more popular, but still a unique natural wonder, is in the interior a bit, Plitvice Lakes. Maybe there’s a spa or luxury place around there. We stayed in a Sobe, a basic but clean, comfortable, inexpensive place, and there are Sobe throughout Croatia.

A restaurant in as Solin served amazing squid ink pasta. Closer to Plitvice, we passed place after place with big metal BBQ contraptions visible from the road. None of them were grilling anything, or we would’ve been there in a instant, but they must throw big feasts when they are operating!

Obviously, you have hundreds of options, but two obvious options would be Dalmatia or Istria.

You could opt for a few nights in Split, with a minimum half day excursion to nearby Trogir. Plitvice National Park is ideally an overnight trip from Split, so you can enter early in the morning. For chill time, head to an island for 4 nights/ 3 days - Stari Grad on Hvar, Vis or Korcula would all be good options.

In Istria, hiring a car is the best way to see the picturesque hill towns if you stayed on the coast in Rovinj or north of there. If you fly into Zagreb, you could easily spend a couple of days there.

I am curious as to "why Croatia?" For the purpose of understanding your travel motivations.
Your help with defining the answer will assist with attempting to create an itinerary.
Note: we view Croatia as two different experiences. 1) traveling by water to visit coastal villages and 2) travel by car to visit significant coastal towns (Split and Dubrovnik come to mind) along with interior journeys to wonderful parks and towns.
I look forward to reading your answer.

This would be my starting point. Have a look on Skyscanner or a similar site for flight choices. Include Venice, it is often used as an entry/exit point for Croatia. Maybe fly in to one airport and out from another.

I honeymooned in Croatia--great choice and especially to wait for warm weather. Late May and early June are good--still slightly chilly sea water but fewer crowds and good chance of perfect weather. I'd take a light jacket or sweater for evenings.
Because getting there from Raleigh will be your biggest challenge, let that help structure the trip. Honestly anywhere you go along the coast will be gorgeous. I'd pick one mainland location and one island spot, so you may end up needing three "bases" depending on logistics. I never drove on four trips, but it really just depends on where you are going.
There are few cities--Split and Zagreb being on only large places and even they are not large. Peruse the Rough Guide--I think it covers the country the most exhaustively.
Just to throw out some ideas:
Split + Vis
Dubrovnik + Korcula
Istria + Losinj/Cres islands (car better for this one)

Did you think about small ship cruising? There are a few companies but we know Katarina-line.com. There is a one way cruise from Dubrovnik to Opatija (and the other way) which we are taking Sept 2020. You could spend 1 night in Dubrovnik, cruise for 7 nights, ends in Opatija. It stops at a different port each morning. They average about 30 passengers per ship, with private room and bathroom. The price for the one we are looking at is around $2500 pp. Not outragous for a honeymoon. Breakfast and lunch included. Since they are small ships, they tend to dock very close to the city center with a very short walk. You could spend 1 night in Opatija then take a bus to Zagreb for your final night. The bus is about 1.5 hours and very inexpensive. They have other shorter cruises, but his one takes you all the way up, or down, the coast. Read their website, it gives information on each cruise and each ship.

Consider renting a sailboat or catamaran and a captain for a week. We did a week sailing out of Trojir - visited 5 islands , ate local, our captain was born on Vis so he had loads of information for us about each island. It really was a great way to experience that part of Croatia.