I have done one cruise before with Disney and travelled with 3 friends, one couple who cruise often on Explorer of the Seas, and one complete newbie.
Embarkation was a breeze, although our email we received days before said to show up between 14:30 - 15:30. We left our AirBnB in Barcelona at maybe 10:15, and were at the port shortly after. We snuck in with our friends who were in a junior suite although we were only in a CP View cabin and were given group one and told it would be a 45 minute wait or so for boarding to commence. But we were happy to have group 1. However maybe 10 minutes later they started calling group 1. By the time we made it to the elevator to the gangway they were already saying group 1-25!!! So really fast boarding. I am a complete newbie to the Oasis Class, but I did get a feeling the cruise wasn't by any means sold out though. Which would make sense at the end of the Summer season like this.
The ship was impressive and lived up to the hype of the Oasis class. One thing I had read online and also that my friends who cruise on other ships also noticed along with myself is that the ship really is very interior focused, and even the few spaces on the main decks that do have windows/portholes for some reason have frosted or vinyl'd over glass. You could easily go a day on this ship and maybe only see the water once or twice.
Actually nice and spacious for the two of us sharing with bed separated. Could get a little stuffy, but loved the little seat beneath the window into Central Park. Fairly close to forward lift lobby.
A quick Day on this cruise. All Aboard was 4pm!
Do Cinque Terre if you can, stunning, and some great walks/hiking to be had.