I have taken many cruises, but this was my first Disney cruise, as was it for my client. She is 88 years young and cruises with her son and his wife annually, but we transport her throughout the ships using a wheelchair.
We reserved a "Handicapped Stateroom" for her and I to share, which was roomy and very accessible to her WC. The bathroom had many grab-bars, a pull-down seat in the shower, but the sink was mounted too high for easy access (although a WC could be pushed underneath it).
Many of the thresholds where carpet connected were a bit high to ride over easily, "bumping" the guest hard. Maneuvering the WC through the seating in the restaurants was always difficult as pathways were narrow; we notified them in advance that we would have a WC but no accommodations in our assigned seating were made. That said, the staff was always ready to help clear a path or guide the WC to the table, to make it as easy as possible.
Half of the doors to outside areas would open automatically and those that didn't were often opened for us by other guests or staff. The elevators are very large and guests were very accommodating of her WC.
Access to the main theater for the evenings entertainment however was so involved and time-consuming, we went to only one show. It required showing up to the show a half-hour earlier than the show starting, being led by a cruise member down the elevator to a lower lever, ride through a hallway to a service elevator that brought us back up to the floor level of the theater, and then set in designated WC area. After show, once the theater emptied completely, we had to wait our turn (there were 6 other WC or motorized chair guests waiting too) for the one and only crew member assigned to come escort each of us back to the upper floors again.
Despite some of the access challenges, our adult-only group had a great time aboard the truly beautiful Fantasy. The adult-only areas might have children passing through them, but not using the areas. Parents monitored their kids in the restaurants and staff kept them amused. The food was excellent, the service wonderful and always with a smile, and the assortment of movies available whether "On-Demand" in your stateroom, outside and above the pool, or inside a real theater, was unbelievable! I wish there had been more free services at the Spa besides the changing area and the steam room, such as a mineral pool or jacuzzi, but there wasn't. I missed not having a casino on board too, but I guess that might not be considered "family-friendly". Would we go Disney again? Probably not, but only because it really is best for families and especially children!