At first I started taking the M2 green line to the Loreto station to change to M1 red line to Rho-Fiera, the Expo site. I didn't feel like walking from my hostel to the Lambrate station then having to walk up and down their stairways. The subway system here in Milan are not as accessible as it's in America, because of ADA. Instead it's less stressful to just walk to the corner and take bus route #81 to the Lima station and go from there. It's more enjoyable to see the sights above ground than the dark tunnels.