Driving from Florence to Milan

Relatively big cities with a ZTL like Bologna and Parma would force you to park far from the city center while leaving luggage in the trunk. Between Florence and Bologna there are the Apennines with their pictoresque villages, but I doubt you are going to exit the A1 to drive in the mountains.

That leaves zillions of food-obsessed villages in Emilia Romagna. I like Fidenza: https://www.italia.it/en/emilia-romagna/parma/fidenza

Thank you! That’s exactly the kind of advice I was looking for.

If all you need is a lunch stop to break the monotony of the almost 4 hour freeway drive, then I would stop at an Area di Servizio (rest area) all of which are equipped with restaurants, shops, gas stations.

Otherwise any stop outside of those service areas, will require exiting the freeway, pay toll, then re-enter the freeway system at a toll booth later. If you want to see some nice scenic drive between Florence and Bologna you can take the old freeway A1 Panoramica, through the Apennines mountains. If you take the new faster VARIANTE DI VALICO, you will be underground in very long tunnels most of the time. The old and the new A1 run almost parallel and north of Florence the freeway splits and you can choose either route.

Along the way there is Bologna, Parma, Modena, but all have traffic restrictions and represent a detour from the freeway. Castelvetro is a nice small village but requires a bit of a detour from the freeway.

My favorite stop driving from Florence to Milan is Parma. I park at the Toschi underground parking - very central and looking reasonably safe, and have lunch at some restaurant in the center (my favourite one being Trattoria Rigoletto).
Fidenza has a large shopping outlet near the highway exit, so it could be possible to eat there - I could not tell about the parking. Another favorite of mine is the Salsamenteria Verdiana, a deli shop in the center of Busseto. Busseto is so tiny that you can cross the center walking in five minutes, but parking is only in the street.
I had lunch once at the Firenzuola autogrill and it was not bad at all, but it was several years ago.