Let me start by saying we picked this trip for our Anniversary based on the cost to get away for a few days as we have a trip to Europe planned next month.
We flew into Miami the morning of departure, which I do not recommend. Due to weather up north, we weren't sure we would get out. We ended up getting out fine. Took a Lyft from Miami Airport to the cruise terminal. Definitely do this as it's the cheapest option (approx. $18 each way). Embarkation were extremely smooth. We were on the boat within 15 mins of arriving! They now have portable kiosks setup and the Carnival Representative just scans your boarding pass and passport. As easy as that! The sail and sign cards are available in your room mailbox when you arrive. I thought at first this was a safety concern, but they stress if the envelope has been tampered with, go to guest services and they'll take care of everything. As the rooms were not available until 1:30 PM, your printed boarding pass acts as your sail and sign card and already has your unlimited drinks package added to it!
We reserved a porthole room on the 7th deck towards the front. As this is an older ship, you can feel the movement a bit more, but I would definitely recommend a room at the very front or very back as the hallways tend to be a bit noisy. Our room steward, Dewa was great! He knocked on our door to talk as we were getting settled in and had us fill out a survey for when we wanted our room done up. This was very new to me as I was used to having the room made up in the morning or evening. You CAN select both. As I know how hard these stewards work, I elected for AM only to make his job a bit easier. We brought a bottle of champagne from our honeymoon to drink on our anniversary and Dewa made sure he put it in a bucket of ice for us so it was chilled. He also presented us with a gift card to the spa to use. I know this was from Carnival, but he had a nice written note to accompany it.
Cabin had plenty of room for 2 of us. The bathroom had a nice layout and was actually one of the biggest I've seen on a cruise ship. The cabin was away from the noise.
Take a Lyft from the airport. Cheapest option.