I believe that this ship is identical to the Ryndam and the Statendam, which we have been on several times. Which cabin are you in? Some of the "accessible" cabins on this ship are less accessible than others (they are much smaller and have a tub instead of a roll-in shower).
Otherwise in spite of their age we have found these ships to be quite accessible, including the tender lift they have. The drawback for the tender lift is that it can only be used with certain tenders, so you may have to wait for some time to get on/off, and it can only be used with a manual wheelchair of 18" or less (no scooters, no power chairs).
Show room is good...you can pretty much sit where you want on the main floor (not in the balcony), and the dining room is fully ramped. Crow's Nest is a little bit of a problem as the couches are screwed to the floor and there are some path of travel problems here, but you can get to the windows at they very front of this room pretty easily in a wheelchair. No pool lifts when we were on them, but I heard a rumor they would going to change this. The buffet is all one straight shot...much better than the island set up on Princess which is confusing and difficult to use from a wheelchair. Free ice cream too!
I love the fact that HAL does not use room cleaning carts, so they don't block the hallways as is so common on other cruise ships. The cabin stewards just use a small hand-held basket of cleaning solutions, etc.
There is a decent library, and the movie theater has several areas where you can sit in a wheelchair. Get there early to claim some of the free popcorn.