You could look at Arezzo which is across the valley from Siena. As old as Siena but it was never as populated through out history so the historical center is smaller. The area around the train station is modern and then slowly blends with older parts of the city as you head uphill. It has an amazing main piazza - most famous for its use in "Life is Beautiful" - and a lot of other smaller more "people's piazzas" as well.
It is less dramatic as visually stunning as Siena but that also means less tourism and more chances to eat alongside locals. The local government works to bring in lots of activities and events so it might be worth checking our what is going on while you might be there. Huge antiques fair as well once a month.
It's connected by train to Florence, is close to Cortona and Chiusi for a day trips - although both of those are train then bus because the train stations are on the flat - and is just over an hour from Siena by bus.
Arezzo seems to have little eat and drink places on every alley way between the big streets that head up the hill. Places like Antica Osteria dell ‘Agania, and Antica Osteria dell ‘Agania are good and traditional. very near the piazza is Antica Bottega Toscana which has the real deal in terms of local produce - cheese still wrapped in hay or seeds - and is very much worth a look. They serve wine by the glass as well eats that go with wine as well.
In Lucca there are many good restaurants - nearly any "famous" restaurant - Osteria dal Manzo, Giglio - will probably require reservations a few days ahead. Piazza dell'Anfiteatro is beautiful and worth wandering through at night but is for tourists not locals. If you want to make that scene Sotto Sotto has the respect of the locals so I'd eat there.
I like Rosticceria Da Nonna Tati on the tiny Via Santa Zita - next to the laundromat in an old bakery location. They are doing new things with Italian food, but not crazy, and it's all really good but unusual given the adherence to "nonna's kitchen" in Tuscany.
Best sandwich place: Ciacco on P.za Napoleone. Also salads as big as your head - not kidding - excellent cicchetti as well.
Second best sandwch place - very different sandwiches - Pan di strada - Corso Giuseppe Garibaldi
Both places have excellent Cicchetti as well
Best gelato; Ele (formally De' Coltelli) and Momo in either location. There are other good places but these are the best - ele for wacky combos and amazing fruit flavors.
Best local pizza experience - Pizzeria da Felice - always packed and spilling into the street outside with little quarter given to tourists. Run the way it always has been with pizza and cecina sold by weight. Try the cecina with the pepper when offered.
Probably better pizza but less of an experience is Itaco across town.
Cheaper local wine store: Vini e Liquori di Ugo Massei Via Sant'Andrea, 19 - owner only speaks Italian.
There are musical performances every night ranging from free to expensive opera all over town. Check the various websites but also look at the fliers around town. The Grapevine magazine calendar is a good place to start: https://www.luccagrapevine.com/
Example schedule: https://www.luccagrapevine.com/february2025/WO.pdf
https://eventi.turismo.lucca.it/en/
Hope that helps, have a great trip,
=Tod