@ohmu A transit pass is great. Take a 80 bus (runs every 5 min) along Parc south about 6 blocks to Place des Arts plaza. The concert stages should be up by mid June for free music.

Walking along Ste-Catherine St from there to McGill College Ave, gives you a feel for Downton core. It also on the metro line from Place des Arts.

I would suggest returning by metro to Mont-Royal station. Mont-Royal ave is pedestrianized in summer. Lovely for coffee & people watching!