Toured this ship the last week when it was in LA. We were only able to visit one accessible cabin (A302) of the 28 they advertise. It has a balcony which requires a portable ramp, sleeps two only, but has a fairly nice bathroom (see pictures under title "Wheels 'n Waves" in the Photo Gallery).
The public rooms are fine for the most part, but the Princess Theater is just as bad on the other ships in the Grand Class (Grand Princess). The only wheelchair seating is up a very steep somewhat dangerous ramp, at the top row in the back to the side. There is a hand rail exactly at eye level, and the sight lines to the stage are somewhat obstructed.
As usual, the Princess staff was pretty clueless about what was and was not accessible for entering/leaving the ship, and tried to direct us to areas with stairs for this and theater access. We were unable to view any of the suites that are supposed to be accessible, including one of the "family" suites. The traffic flow in the Lido (Horizon Court) food area, is also poor, esp. for someone in a wheelchair who needs to use a tray.
Long narrow hallways, due to size of ship (2600 passengers), to negotiate (as on the Grand Princess) which can be a real problem when housekeeping carts are blocking the way. Some rooms are close to elevators, but many are not. Some features are different from the Grand Princess (location of public rooms esp.) but basically the same design.