Ciao!
We are traveling to Italy in June. 4 of the nights in Florence. We were going to take a train from Rome to Florence, since we really don't need a car for the majority of the trip. We would like to do a day trip to Siena and wineries/Vinyards around Tuscany. I don't like the idea of a bus tour, plus, the trips include traveling to Pisa, which we are not interested in going to. How difficult would it be to rent a car in Florence for the day?
It is pretty straight forward. You might consider though where to rent. Central Florence (near the train station) has rental offices, but you will need to navigate city traffic and the dreaded ZTLs. The airport would get you away from most ZTLs, and maybe easier to navigate out of town. Another option is to rent in a smaller town near where you want to roam, train or bus to and from Florence.
Read up on ZTLs, bite the bullet and pay for a zero deductible CDW, and you will be fine.
In Florence, we always rent cars on Borgo Ognosanti as that location is easy to get out from the city and onto autostrada.
Wait, is there a lost-in-translation issue here?
So you're NOT going to rent a car because you'll be spending most of your times in cities...
You'd like to do a day-trip to Sienna, and visit a winery somewhere in Tuscany...
You DON'T like bus tours and you DON'T care to visit Pisa...
But, you want to rent a car?
OP would like to rent a car for a day as stated at end of post
Where is the confusion?