Cape Canaveral is easy with a scooter or a walker/cane. The terminals have elevators that will hold two scooters (large size). There are ramps in all curb areas. There port area is very mobility friendly.
You should, however, keep in mind that if you plan to take a taxi, Uber, or Lift from the port area, you will want to make arrangements ahead of time (depending on your walker size). If you cruise is now or through till October, please remember that this is our low tourist season and there are not as many services being offered.
Additionally, Port Canaveral has several dock areas. RCCL has it's own terminal that is convenient to some shopping and restaurant and bars ( a slight walk is needed). There is, however, times when Royal docks at the Carnival terminal. That terminal is not near anything within walking distance. Day stops on cruises out of NY/Bayonne often use this terminal as they have a port day on the same day that a Royal ship is docked at their port on a turn-around day.
Hope this helps!