Serenade of the Seas is one of the easiest ships to navigate. I never got lost the whole cruise. I'm not really sure what made this ship so easy....was it the well placed elevators, was it the touch screens on each floor, was it being able to see every floor from the atrium, was it being able to go front to back on all floors? The planners of this ship certainly had me in mind when they designed it. I am going to miss her when she leaves New Orleans.
Getting to the spa was easy. The massages and facials (yes, I went more than once) were wonderful and worth the money. Lying on the heated lounges in the spa is the best way to relax.
My cabin was close to the stairs and elevators. Even being in a busy area, I was never bothered by loud noise. Do not let convenience of stairs and elevators cause you concern. It is still quiet in your room.
If you want to just walk around Key West, try a few pubs, eat Key Lime Pie, see a museum.....enjoy on your own. No real need to book an excursion. Key West is a nice, quaint town. Since it is a US port, enjoy using your cell phone to let everyone know just how much fun you hare having on your cruise.
Enjoy the beautiful water and beach. There is no charge to grab a lounge chair, eat some lunch, and just enjoy some beach time. Although this is a tender port, do not miss getting off this ship to see the beach.