Hi Elizabeth!
Congratulations on your upcoming celebration with your mother. I always enjoy having girl time with each of my daughters, but enjoying it in "The Happiest Place on Earth" has been the ultimate girl time for me.
For Guests with mobility issues, even temporary ones, I wholeheartedly recommend paying for preferred rooms or staying at Port Orleans French Quarter. I have been in a wheelchair myself at Walt Disney World due to an injury and can testify to how much easier my vacation has been when we have been close to the main areas of the resort hotel. You are not guaranteed a close room if you only make a request on your reservation.
Another suggestion that I have for you is to consider
Renting an ECV or manual wheelchair from a Preferred Disney Vendor. This linked page has vendors and their phone numbers listed at the bottom of the page. If you rent from an outside company then you will have use of the ECV/wheelchair outside of the theme parks that you can use at your resort hotel. One thing to consider is if your mother can tolerate her foot being down all day. If she cannot and you are able to push her, then I recommend to rent a manual (non-motorized) wheelchair
with elevating footrests.
I hop this information helps you in making your vacation plans Elizabeth. Please don't hesitate to write back if you have more questions. We love to help plan vacations here at the Disney Parks Moms Panel!
Have a Disney Day!
Brenda ºOº