This is probably to late to help. Also, please correct me if my memory is wrong. I love this ship but I'm not in need of accesibility features so may be forgetting something.
Everything (at least everything we use) should be acessible. Just watch out for which door you use to go out on deck. In some places on deck there will be one sliding door and one door that has a handle. The sliding door looks like it would be easier to get a chair/scooter over the door jame. There are places where there are stiars that look pretty and serve a purpose but there is a way to get to these floors pretty easily without taking the steps. The main place I know of that might get tight is the photo gallary when they've just put pictures up and its just before supper. This isn't because its inaccessible in the true sense of the word. The place just has a lot of people in it at these times which makes the space more crowded.