I have only rated this as 2 because there were 5 cruise ships in and walking around was almost impossible. It was like sardines. They are going to ruin these lovely small ports if they allow this many ships in. There were 9000 cruise pax on the day we were there and aparently in August there were 15000.
Dubrovnik is very easy to do by yourself. We never take an excursion if we can help it.
Corfu is another delightful place. As we have been here before, we did a bit of research before we went and found that a No. 10 local bus from the main square takes you to the Achilleon Palace and this proved to be well worth it. Bus fare was 3 euro return and the Palace was just beautiful. We then caught our return bus and wandered round the streets of Corfu/
Venice is of course a lovely port. We walked from the port to the People Mover which costs 1 Euro and takes you to Piazzale Roma where were bought our all day Vaporetto ticket - 18 Euro and we visited Torcello and Burano. Burano is where they make lace and is like a mini Venice. We really enjoyed our 2 hours there.
We then returned to Venice and did a little shopping and returned to the ship the same way we started.