With a scooter, I would highly recommend Beach Club or Yacht Club. Easy, scooter accessible, ferry over to Epcot (ideal back entrance into world showcase) and DHS You can also get the boardwalk area via ferry, nice to visit at night. Both resorts have much more spacious Disney transportation options and great dining options.
The GF seems most spacious of all the monorail resorts. GW at the Contemp would have you going to another building, up an elevator, then a hairpin turn n the monorail line.
At the Poly, again a tiny elevator to the second floor, but once you are on the second floor, it gets very spacious and manageable for a scooter.
Keep in mind on the monorail loop, you need to get off at the TTC (or go directly there from the Poly), down a huge ramp, then up another to get to the Epcot monorail. The lines are extremely long inthe evening to get back to the resorts as every guest uses it as a shortcut to get back to the TTC rather than the longer lines of the express (now the lines are about even).
I walked back to the YC from Epcot and it took me 4 minutes. I imagine in a scooter its a little faster! Beach Club is even closer, but really just a minute. The accessible rooms at YC are on the second floor, extremely close to the common areas, pool, lobby, shops, dining but around a corner that you do not hear any noise (my mother stayed in one last trip). It was fabulous for her and for us that everything was so easy and convenient for her.