Hi, sorry for the late reply. I was in Cuba and the internet connection was rather bad.
I have not taken the cruise and the cruise ship dock is only accessible to paying customers, so I do not know exactly what the inside looks like.
But, I do know that I have booked several taxi tours for people with impaired mobility. These individuals must have gotten off the ship somehow. Plus, all the cargo and baggage must get on and off the ship using elevators. I am 99% certain that there must be some elevator for passenger use. Wheelchair use in Cuba is common and Cuba has one of the oldest populations in earth, so a lot of the new infrastructure takes into account mobility.
I’m pretty sure it will not be a major issue to get the wheelchair and person off the ship.
take care,
Mario
