Serenity Bay (adults only) requires one additional tram ride after the drop off for Family Beach / shopping / Cookie’s BBQ. No additional walking between trams.
They will need to walk from the ship to the first tram station. It will take 3-5 minutes, depending on walking speed.
[And you have to step up into the tram (think WDW parking lot tram. It’s no effort for most, but for some with weak muscles, it’s a high step. Strangers always gave me that needed boost.). They can accommodate wheelchairs.]
The drop off is right at the beach. It requires walking through sand to get to the loungers and water.
All loungers and beach chairs are low height. There are a few hammocks. Umbrellas. All free.
The bathrooms are right T drop-off and in the building with the bar (requested adult drinks). This has seating that is normal height.
Serenity Bay has its own lunch area. It has similar food as Cookies, but is also limited to 18+. They also have a grill with sirloin, ribs? and fish. Soft serve ice cream and fountain sodas are right there. Seating is at picnic tables on the sand. Under trees and umbrellas. (Cookies’ seating is in a pavilion with a solid flooring - but also picnic tables.
Lunch is served for ~ 2 hours. The bar will be closed by ~ 3, 3:30, as most guests have left before all aboard at 4:30.
Serenity Bay water is shallow for a long way out. Some rocks on the seabed; not a lot and avoidable. Very little wave action and very clear water. Typically warm water.
Think of it as a day at the beach; very relaxing.