Getting to Piazza Michelangelo and San Miniato al Monte

You can walk it in less than 30 min, slow pace. The portion uphill is "the Rampe" (the ramps) which is the portion from Piazza Poggi up to the Piazzale, which is basically stairs going up through the gardens along Viale Poggi.

From Piazza Pitti to Piazza Poggi, it's flat.

San Miniato is basically a 5 min walk from the Piazzale. There are some stairs to go up, but not too bad.

Taxicabs can take you there in less than 10 min.

If you don't feel up to the walk, take a taxi up and walk down (as the Italians say: "When you walk downhill, all Saints give you a hand".)

I've walked up to the church a few times, but I hike and walk regularly. I'm in my late 50s for reference. The chanting was truly amazing and not to be missed, especially since your wife loves it. On the way up, I passed many people going in both directions. There are places to stop and take a breath along the way, so I'd say if you can't find a ride, just give yourself plenty of time to walk, knowing you might take breaks along the way.

I'm always amazed at how quickly I get helpful responses on this forum . . .

So it sounds like we could take a taxi, but if I can't get one the walk isn't too awful. That's encouraging. We're walking around Palazzo Pitti and Boboli Gardens in the morning, and have the whole afternoon to check out Alt Arno and then get up to the piazza. I'll do the taxi if I can - it will just help me avoid a lot of knee pain if I can avoid climbing a hill like that.

We will walk if we have to. My wife knows nothing about San Miniato al Monte. I've kept that a secret so far. Hearing the chant will be a big surprise for her. I'll crawl if I have to. But taxis are a lot more comfortable. LOL

From Boboli there is a taxi stand right in front of Palazzo Pitti, across the piazza.
If you exit the gardens at the Porta Romana gate, there is a taxi stand at the Porta Romana gate, across the Piazza at the corner with Viale Machiavelli and Viale del Poggio Imperiale.

From someone who was last in Florence before their knee replacement- if you have bad knees, do yourself a huge favor and take a taxi all the way up to San Miniato. Just getting up the stairs to the church from the street below almost did me in. Then walk down from there to Piazza Michaelangelo and the Oltrarno area. You're welcome.

Or … you can take the #12 or #13 bus. It’s quick, efficient, and inexpensive.