My mom cruised the Wonder to the Mexican Riviera with us. She rented a powered wheelchair, and it actually worked out wonderfully for everyone. She was able to park her chair outside of the state room in the hallway. There were outlets out there for charging about every 20 feet or so, so while there might not be one right next to your stateroom, it should be close enough for you to walk back to the room with (or maybe even without) your walker.
As someone said, the elevators can get a little crowded, especially during meal times. I would suggest using the forward elevators during mealtimes, as all the restaurants are in the back.
The doors leading to outdoor areas of the ship have a steep up/down ramp leading to them, and the chair being a "low rider" got stuck on these a couple of times. The forward elevator lobbies had the best entrance/exits on deck 9 and 10, so that's another reason to try and stick to the forward elevators.
One more thing to consider that we didn't think about before the trip. Mexico is not as accommodating to wheelchairs as the US is. we wanted to explore the area around the ship and go to
WalMart and the mall near the boat in Pureto Vallarta. There are no ramps at street crossings. My mom had to get out of the chair and my brother and myself had to pick the chair up and set it down so that she could cross the street. Not a fun thing to do when crossing a busy Mexican street. So please be aware of that should you want to get off the boat, I would recommend doing excursions through Disney and making sure that they are wheelchair friendly.