My wife and I are visiting Croatia for the first time in Sep and we need help to complete our 8-night trip itinerary. Below is the brief outline of our current itineary:
- flying in to Split on Sep 16 and will stay for 3 nights and plan on doing a day trip visit to Trogir and rest of time just roaming around to enjoy the splendid historic city.
- Boat (Catamaran) to Korcula for 2 nights. We are not sure if we should stay just 1 night and spend more time either in Split or Dubrovnik.
- Boat (Catamaran) from Korcula to Dubrovnik for 3 nights where we will do day trip to Kotor area in Montenegro
We will stay in the old city near the pier in Split. Likewise, we will stay near the old town in Korcula within walking distance to the pier. The Catamaran pier in Dubrovnik is way out of the Old City in Gruz, so we are not sure where to stay in Dubrovnik, within the old city wall or outside? Is Gruz the right place to stay for 3 nights and if so how convenient it is for local transportation? Thank you in adavnce for any suggestions made to this post.

If it were my trip, I would spend 2 nights in Korcula. We did not visit Korcula but keep in mind that 2 nights gives you one full day, and maybe half a day on the day you arrive, and maybe another half a day on the day you leave for Dubrovnik. Obviously, this all depends on what time you arrive on Korcula and what time you depart Korcula.

I like your allocation of nights for Split and Dubrovnik. We spent 4 nights in Split, and that included a day trip to Hvar and a day trip (more like 3/4 of a day) to Trogir. Because you are staying in Korcula, you don't need to go to Hvar so I think 3 nights is perfect. While in Split, in addition to wandering around this beautiful city on our own, we also hired a guide for a 2-hour private tour of Old Town and Diocletian's Palace. We also really enjoyed the Ethnographic Museum.

We spent 3 nights in Dubrovnik, and that included a day trip around the Bay of Kotor. We hired a private driver for this trip. If it were me, I would stay inside the walls. We enjoyed the ambiance and the convenience of staying inside Old Town. In case you are interested, we stayed at Karmen Apartments, about a 5-minute walk from Ploce Gate.
Apartments within medieval walls - Home

If you wish, you can click on my name to read my trip report from September 2019.

Based on past experiences I found staying outside an old city would allow us to better explore a place by walking the stretch of the city. Also, I tend to find best places to eat are usually away from main tourist area. I have looked into Karen's Apartment which has very good reviews and I definitely will consider it. Is Dubrovnik a hilly place outside the old city wall as this will be a big factor (negative) for us? Is there a train station in Dubrovnik and if not then where is central hub for local buses?