But you should always bring a map with you to the rental office and have them show you the exact rou

I'm getting close on planning cie tours international out my 4 day path from Florence to Orvieto! I have decided to take your good advice (thanks pizzocchieri) cie tours international and travel fairly directly on the first day from Florence to Pienza (home base), traveling through Chianti, etc.. on the way down. I am hoping for a bit more of your wonderful cie tours international and generous advice on another detail...
I've been checking out rentals on Kemwel (thanks Zoecat for the tip!). It looks like picking up the rental car at the Downtown office on Via Del Sansovino is both more economical and also a bit closer and more convenient to starting out through Chianti, yet will still let me drop the car off in Orvieto. Sounds good to me, but am I missing something? I'm assuming that this location is not in the dreaded ZTL zone, but am I wrong about that?
But you should always bring a map with you to the rental office and have them show you the exact route. Because sometimes the cars are parked down a side street, or there can always be detour for road work. So double check what you've scoped out with the rental office.
You should also plot out and have with you the fastest way to get from Florence to your southern Tuscan hotel. Just so you have it with you on that day in case you change your mind and just want to go straight there.