The garden wing was renovated after the main tower. It is by no means in poor condition. Some may not like the design, but that doesn’t make it poor condition. You can request a 1st floor room due to the mobility
scooter & might have a better chance because of that.
We like the quiet of the garden wing & the easy access to the main area without needing an elevator. We can take the escalator to the monorail or dining & shops & not need an elevator. I think you’ll find the elevator situation with a scooter in the main building difficult at times. The elevators are not big there either & often crowded.
As for room availability, are you looking at discounts or rack rate? Sometimes the website defaults to a discount that shows no availability. But changing to rack rate will give different options.