Mobility Issues
Buongiorno -
I believe a DIY visit to Tuscany / Italy
could be possible for someone who has mobility issues - but only if you know how to manage your expectations. Somethings simply will not be feasible. For example, off the beaten track will be less likely.
You can find wheelchair assistance in the larger cities, and if you plan accordingly there are several smaller tours you can add to your agenda which will make it possible to not miss out on the "fun stuff".
I suggest the first thing you do is create a bucket list for the two of you, and then examine who those activities should be done, perhaps you can insert those "must-do's" in between days hanging out in a scenic spot. For example, one day visit a winery and Greve-Chianti (one of the few flat towns I can think of in Chianti

) and then the next day spend it at your B&B in Chianti, with a cooking class in the afternoon. Or have a NCC (driver with car) take you to Pisa & Lucca with the wheelchair (they know where to park to get you as close to the attractions as possible) and then the next day do a leisurely breakfast at your accommodations, and some people watching at a little town.
I also suggest you read this article:
https://www.visitflorence.com/moving-around-florence/physical-disability.html
and definitely looking into booking your museums with a guide, who can move you through with a wheelchair.
Once you have made a list of places, you and your mother really want to see, let us know and we will try to give you some insider ideas on how to visit them.
Buon Viaggio,
Donna Denise