Florence things to do...

Florence:

https://www.visitflorence.com/

Statue of David/ Accademia Museum http://www.accademia.org/

Florence day trips and excursions: (Lucca, Pisa, San Gimignano, Siena) https://www.viator.com/Florence-tours/Day-Trips-and-Excursions/d519-g5

 Basilica di Santa Croce (if open, is really worth a visit. They have a guided independent tour-brochure and headphones, or you can take a guided tour. Don’t miss the cloisters.  Galileo, Michaelangelo among many other famous people are buried here).  http://www.santacroceopera.it/it/default.aspx

Basilica di Santa Maria Novella: Amazing church, grounds.   https://www.smn.it/it/

Basilica di San Lorenzo: another amazing church, outside rather plain, inside a gem. Leather market surrounding it. http://basilicadisanlorenzofirenze.com/

Ponte Vecchio, shopping (jewelry) but just nice to walk over the river.  https://www.visitflorence.com/florence-monuments/ponte-vecchio.html

Ufizzi Galleries, Pitti Palace and gardens across Ponte Vecchio  https://www.uffizi.it/en/pitti-palace

Piazza Michaelangelo: best view of the city, walkable to get here, and at Sunset, fantastic views. Another copy of the Statue of David here.  https://www.florence-museum.com/piazzale-michelangelo.php

City Museum/ Bargello Gallery- Statue of David outside (3rd of 4 copies), Open air sculpture museum, Neptune fountain. http://www.reidsitaly.com/destinations/tuscany/florence/sights/bargello.html

 Duomo, Bell Tower, Baptistry, Dome: I would probably use Viator or City Wonder Tours to skip the line, and have an English Speaking guide take you through.  A store, Rinascente, has a restaurant on like the 5th or 6 th floor, and you can have Tea up there while enjoying the best view of the Duomo in the City.  https://www.ilgrandemuseodelduomo.it/monumenti/1-cattedrale

Never enough time in either of these cities:  Do your best!!!