We stayed in a very basic B&B, 4 Rooms. It was located at the area right outside the entrance to the main Piazza. It's where the tour bus drop-offs are and a ton of Souvenir booths during the day (the booths close in the evening), so not particularly peaceful during the day, but we had breakfast then were out for the rest of the day, so not bothered by that. Our friends stayed at another B&B, 7 rooms, located on Via Santa Maria, which is the main drag off of Piazza Miracoli, where all the touristy restaurants are. Both had stairs to get to rooms. Our friends rented a car, and found street parking nearby (I think they may have needed a special permit to park there which I believe you can get from police station, but not 100% sure. Our friend has mobility issues so may have gotten permit because of that.). We did book our tickets to climb the tower (I love going up in towers just for the views) in advance and it was a timed entry. We got a combo-ticket day of, to visit all the the monuments/museum in main area.

Thank you very much, MFNYC.