All car rental returns are at the following multistory garage, located 3 blocks from the main Florence train station (Firenze Santa Maria Novella Station), less than 10 min walk.
Set your navigator and Google Maps is smart enough to send you the right way without incurring into the ZTL cameras.
Be aware that this location closes at 7:30pm (and maybe sooner on Saturday) however it is possible to return the car after hours (possibly for a small extra fee).
Garage Europa
Borgo Ognissanti, 96, 50123 Firenze FI, Italy
+39 055 292222
https://goo.gl/maps/9UarMy3xTbn
Avoid the Piazza Stazione itself for hotels, it’s rather noisy.
Look into hotels located on Piazza Santa Maria Novella or also on via della Scala, but as close as possible to Piazza Santa Maria Novella.