How is it renting a car and driving to that area? Running out of choices, train strike all of a sudden.
Go to AutoEurope.com and see what rate they are offering
A one day rental is probably in the 100 euro range.
Drive should be about 3 hours- easy on A1 etc- no different than driving on interstate in US.
You will need to be careful leaving Florence and entering Verona- to avoid ZTLs and possible fines. To avoid you could pick up /drop off at the airport locations
I don't know if rental agency will ask for an IDP- it is required by law- so you won't have that and take a chance. If rental agency does ask and you don't have they can refuse the rental.
If you are stopped and asked for it there is a fine of about 400 euros.
Is bus an option?
Check Flixbus
You other post is confusing- are you also driving to Cinque Terre?
https://community.ricksteves.com/travel-forum/italy/train-strike-while-in-florence-should-i-drivwto-cinque-terre
If you are not now in possession of an International Driver Permit, then you cannot legally drive in Italy. Have a look at Flixbus. They should have several per day.