We got free flight tickets to Milan in the middle of March and we're trying to decide if to go or not. Neither of us is much into fashion or shopping, so it seems a lot of the most well known attractions in Milan are not relevant to us.

Would there be things worth doing in the surrounding area in March?

Milan is a lot more than shopping. We were there in September for three nights. We could have added one or two more nights. Check out the report below (Chapters Two - Four ... lots of photos).. Milan is very underrated. Great food, people and sights. I have no clue why people give Milan short shrift. Get timed tickets for Duomo and terrace.

https://travelswithmaitaitom.com/italy-2018/

Milan was not my favorite Italian city but I agree with Maitaitom that the Duomo is worth it. In addition, you can maybe see if there are available tickets for Da Vinci's The Last Supper, which was my main reason to visit Milan and I do not regret visiting it at all - that is if you're interested in art. Also worth noting is Castello Sforzesco. Not the most impressive castle but interesting history nonetheless.

If none of the above interest you, I suggest going research of the surrounding areas to see if something strikes your fancy. It would help, too, to let us know what you are interested in to provide suggestions.

Milan, for us, was one of the more disappointing places in all of Italy. But it was worth a couple days for the places mentioned by others. We liked Bergamo which is usually off the radar of most people. If you luck out and get good weather, you might go to the northern lakes. Milan is one of the best rail transportation centers in Europe, and you can easily go to Turin, Bologna, Ferrara, Parma, Modena. A little longer rail trip can get you to Verona, Venice or Rapallo and the Italian Riviera. March isn't the best time in northern Italy. I would go, but plan to be flexible, depending on the weather. No need to worry about advance reservations.