So, I will be concluding a 17 night trip to Italy in May with 3 nights in Bologna (arriving Wednesday, May 20, departing Saturday, May 23) by traveling from Bologna to Milan Malpensa where I have my final night booked at the airport Sheraton, before a 7 a.m. return flight on Sunday morning.

As of right now, I have reserved a ticket (but not paid for) a daytrip tour from Bologna for that Thursday which would take me to a parmigiano reggiano cheese producer and balsamic vinegar producer somewhere around Modena, but I'm thinking about using that final day of travel to stop either in Modena or Parma for the day (storing my luggage at the train station) to see something along the way (I will have spent 3 nights in Milan at the start of the trip).

Any thoughts regarding the feasibility of this, and whether Parma or Modena would be better for my final day diversion? I've done a little looking at Modena, and the Enzo Ferrari museum looks to be a little interesting, along with the duomo and main piazza. I haven't done much looking at Parma at all, but the train connections may be better there than in Modena.

I'm not 100% committed to the Thursday tour, but it seems interesting enough to me. I will not have a car for this part of the trip, so some kind of guided tour seems to be the only logical way to see the cheese production process, which I'm most interested in, although I have seen some folks say not to waste time on this type of tour.

If you're into supercars (Ferrari and others) and auto racing, the Enzo Ferrari Museum is great. Walking distance from the Modena train station, interesting architecture, nice bit of Ferrari history (Enzo's original office and "factory"), and a very good display of beautiful cars. More interesting than cheese and vinegar making, but that's me.

There isn't luggage storage at either the Modena train station or the museum, but there are options nearby.

We’ve done a food tour with Italian Days twice. They picked us up in Bologna and took us to Parma for a tour of Parmesan being made, then to a small producer of balsamic, and finally to a prosciutto place, then lunch and the drive back to Bologna. We enjoyed it. We’ve not spent any time outside of the tour in Modena or Parma but a friend really enjoyed Modena.

"I haven't done much looking at Parma at all, but the train connections may be better there than in Modena""
All Milan bound trains stopping at Parma stop at Modena too.
Pamra haas a historic city center with cathedral and battistero, a outstanding Art Museum ......
It's all up to you