I flew with Ryanair from Madrid into Milan and took a train to my Airbnb about 25 minutes on foot from city center. Day one I spent wander around the city, taking in the sights and sounds. The Leonardo Da Vinci museum was beyond interesting
Day two I took a tour (I forget the company name, but they were the top listed on a few different travel sights) to Lake Como. We got a short tour of the town before getting on a boat that took us a couple hours across the lake the Bellagio where we were able to explore and get something to eat. It was one of the highlights of the entire trip.
I flew out early on day 3. Tried to take the train to the airport, but trains don't open as early as I was hoping, so make sure to check what operating times are so you're not stuck like I was. I ended up walking for about an hour and a half before I was able to get on a train to take me the rest of the way to the airport.