I have stayed at Boardwalk Inn in a wheelchair Access room several times before becoming a DVC member.
With one exception (more later), I have always stayed in an adapted garden view room. I believe these rooms are currently combined with, and re-classified as 'standard' rooms.
Although the rooms I have stayed in have been on different floors, they have always been in the same position. They are the room closest to the elevator lobby and ice machine facing the garden. (you cannot hear them) They make the corner, so the rooms are wedge shaped, normal room width at the window/balcony end and one and a half rooms wide at the corridor end. The rooms are therefore a lot larger than regular rooms with large bathrooms/shower areas. One year my wife & I had two
ECVs in the room. There was plenty of room to park one up for charging with space left over to drive figures of eight without hitting the furniture.
Avoid the room on the first (ground) floor unless you like being in a dark hole surrounded by plants. The other floors are great, and you will get a good view if Illuminations from 4th & 5th floors. I think 5th floor has a bath with transfer seat rather than a roll in shower though you need to double check.
My one exception
One year, Boardwalk/Central Reservations fouled up and they didn't have a wheelchair room with roll in shower for me although I had booked one. After waiting for an hour for them to come up with a solution, I said that I would do without taking a shower or bath my first night, provided they could move me on the second. Big mistake! The so-called wheelchair room I was given was a regular room with an enlarged bathroom (and smaller sleeping area as a result). It had a regular bath but with extra grab rails. Wider door and a little extra space. Grab rails around toilet. The sort of room you find in hotels that have adapted a regular room for wheelchair use. The main sleeping area was too small to move around in easily.
I have never stayed at Boardwalk Concierge of in a lake view room, so cannot give you any advice regarding the more expensive rooms.
Andrew