We just left recently, and need a roll in shower for my daughter. If you need a king roll in shower room, it is a bookable category. When you book the room, you NEED to check "handicapped accessible" room to check availability. Then you can see if they have KING rooms with ROLL IN SHOWER. There are not a lot of them. The roll in shower has a seat (which she needs), but be warned, the bathroom will get very wet (we used a few extra towels to dry the floor).
We had booked a preferred room, to be close to transportation.
They have very few of these rooms.
We were in room 1318.