Two Days in Florence - Bad ankle!

[Carouselfish]

Taking my mum to Florence. She has a recurring ankle problem that makes a lot of walking rather hard. Despite this she manages an hour dog walk a day, so it's not as bad as some. We are staying in Piazza Piave.
Any recommendations for attractions - we want to do two per day so two pairs of close together ones would be ideal.

Florence is very small so a good destination to pick - on the downside a lot of the attractions are museums and churches with not many places to sit.

From Piazza Piave I would go to Santa Croce - which is huge so might take a long time.

I'd also go to the food market at Mercato di Sant'Ambrogio.