Emilia Romagna recommendations

Parma has a wonderful cathedral and baptistery. The inside of the cathedral dome was frescoed by Corregio. It's also famous for food. Think parmigiano and prosciutto. Modena is very close by.

Bologna, for food, history, relaxed atmosphere, proximity to Pisa and auto plants (Ferrari) etc. for day trips.

Parma is a lovely city with wonderful food, an attractive cathedral and baptistery plus convenient train connections to Modena and Piacenza. It is also close to Bologna but is much easier to navigate than Bologna and is more "laid back." If you go during the Verdi Festival, you will have an opportunity to hear some of Verdi's less frequently performed operas. The art museum is worth visiting and I found the staff in the Tourist Office to be very cordial and helpful. Emilia Romagna is a real treasure - enjoy your visit in whichever city you decide to visit.

Modena similarly has a really amazing cathedrale.
The food is both what we would think of as quintessentially Italian, and amazing. Between Parma, Reggio-Emilia Modena come a holy trinity of foods... Prosciutto di Parma, Parmigiano-Reggiano and Aceto Balsamico Tradizionale di Modena (and di Reggio). In Modena, if you are spendy and into modernist cuisine is perhaps the finest restaurant in the world, Osteria Francescana. In Bologna, is the ragu, the lasagna, the mortadella. Elsewhere in the region is the culatello di Zibello. Throughout the region is pasta made with so many eggs it is wonderfully golden and rich. In Bologna you find the culinary capital of Italy, with many Italians conceding that E-R has the best cuisine. Bologna needs an exploration of the Quadrilatero, and maybe a cooking class. When researching, I wanted to go with this company:
http://www.taste-of-italy.com/p/cooking-lessons.html

For wine, lambrusco is light, bright, acidity, frizzante and red. I love it, particularly with the rich food of a rich region.

I think I would do nights in Modena, as it's central to Parma and Bologna.

So glad I asked. Thank you for enthusiastic, informative, experience based celebration of Italian culture unique to the Emilia Romagna region. You have enriched our engagement in designing our itinerary and our anticipation of this wonderful journey. Grateful to all who took the time to contribute. Ciao!

Not on your original list: Bologna, Ferrara, Ravenna should be considered. Can you give this region a couple more nights?