Viareggio

As someone who spent many Summers in Viareggio and Versilia during my teen age years, I can tell you that if it is as hot as it was last year at the end of June, you will be tempted to forget about visiting Florence or Lucca and stay in the area instead. At least you will get some relief from the sea breeze. I don't know what type of transportation you have, but with my motorcycle I could get to the Cinque Terre in an hour or less. An interesting visit would be to the Apuana Alps. That's where the Carrara marble comes from. From Viareggio you can see those high mountains on the East. They seem to have snow on them, but it's actually white marble. Besides the beaches in town, it would be nice to visit the beach between Viareggio and Torre del Lago, along Viale dei Tigli. From the Viale to the beach it's a nice walk through the pine forest. North of Viareggio is Forte dei Marmi, a fancy resort town where many stars have a house. At night the area is full of life along the passeggiata (stroll promenade). You'll love that area, perfect for a beach vacation. That would be memory lane for me. If you have kids with you in their teens or early 20's they will want to stay there and send you to Florence's museums on your own.

Also less than an hour north is Sarzana a pretty little town with a couple of forts. Nearby is Lerici on the Gulf along with Tellaro to experience an old seaside community. Further down the peninsula is Montemarcello one of the 'borghi piu belli d'Italia' surrounded by the Parc of the same name. Here's an article pn Lerici on a blog from the area. http://www.apathtolunch.com/2011/06/castle-to-castle-along-gulf-of-poets.html