Keep the tips coming! I appreciate all your thoughts. So I've officially got the first leg of the trip booked. In Santorini we will be staying in Imerovigli at Astra Suites. In Mykonos we will be staying in Mykonos town at the Belvedere.
Flight is booked from Mykonos to Dubrovnik. From there the schedule is still open with around 7 full days to spend in Croatia (not including travel days in and out). With all this talk about the schedule being too tight I'm considering cutting Split, and just go Dubrovnik/Hvar. Realtogrl do you think that would be a wise move? We could always day trip to Split if we got bored in Hvar? Overall I would say we like to be adventurous and jump around...but again it's our honeymoon and doing that can be stressful / unpredictable, so trying to find a good middle ground.

Our honeymoon is this year so coming up soon. Obviously things could change with COVID so we'll have to be on our toes. Hoping that things continue to move in the right direction.
Love the picture from Imerovigli MoBro! Can't wait till I'm enjoying the same view.

I honeymooned in Croatia and made the mistake of trying to do too much--we had to go back three more times to feel satisfied (and I'm sure we'll return). I'd keep it to Dubrovnik and Korcula (or one of the other nearby islands) instead of Hvar. It's closer, though catamaran times being what they are, it may not make much difference. There is also Mljet and the Elafiti islands just off Dubrovnik. You are moving around a good bit. Congrats!

Gustave, Hvar is a big island. I do not think you will be bored unless you stay only in Hvar town. If you want to cut down on moving around, it’s a good idea. And do visit Split as a day trip. There are morning catamarans going to Split and afternoon coming back… and those are commuter catamaran so not much worry of them being cancelled (except in really bad weather, but in that case there is a car ferry.) The catamaran from Dubrovnik to Split) stopping in Mljet, Korčula and Hvar is the one that is sketchy. They are mostly for tourists.

Gustave, I hope you love that Imerovigli spot as much as we did!
Here are some notes regarding restaurants nearby, and things we did in 2016:

"Imerovigli has a bus stop and is easily served by taxis. It's a tiny town, with a market and a cafe or two. In the middle of the caldera.

We found a fabulous little restaurant that's on the walkway at the top of the caldera, about 10 minute walk from our hotel, the Gold Suites, going toward Fira.
It's called La Maison (which is a bad name because it's not French). It has an amazing location looking over the water. It's simple & contemporary, with an exciting menu and good service.
I had a local fish, wrapped in seaweed and fried till crisp, with lime foam. And my appetizer was a wonderful scallop dish.
http://www.lamaison-santorini.com (Reservations a good idea, if they are taking them.)

Another restaurant we liked a lot, was just before the La Maison, on the opposite side of the path. Larger and much busier, but good food and service. (Can't remember its name, though)

Also, we took a half-day sunset swim/snorkel cruise. We chose a boat that only had 14 clients on it, arranged through our hotel. They grilled shrimp and chicken for dinner. Lots of drinks of all kinds available all day. Very nice.

We walked to Fira. Really beautiful walk along the caldera. About 20 minutes from our hotel. The town is too touristy for us, being right at the ferry dock.

We took a bus to Oia for the afternoon, from Imerovigli. Oia is a classier town than Fira. More expensive. Lots of jewelry shops. Still touristy, though.
Too crowded for sunset. Better views from our hotel patio @ Imerovigli."

Would love to get your itinerary of what you ended up doing. Booking to go mid-September