It was awesome, and I think about Montreal often...
I planned my daytime activities (sightseeing, restaurants, etc.) but my night time activities were more fly by the seat of my pants. I looked at all the agency websites prior to my trip, and made my "to-do" list. Once there, I looked to see who was available that night, and made the appt. Fortunately for me, everything went as well as possible and I saw who I wanted to see.
Though it was my first time to Montreal (definitely not my last), it appears that much can be accomplished without a plan!