I'm looking to visit MTL during POP Montreal, which is from September 21- 25. All in all I'll be in the city for a week. I understand that POP is a more leisurely festival than other events such as Osheaga or Coachella, one can basically visit the different acts by traveling to different bars/clubs in the city, it's not set at a dedicated festival ground. My question is that in addition to the festival, would a week be more than enough for a first time visitor to the city? Might it be too long? If so, what other places in the area are worth visiting? I was considering looking into ways to visit Quebec City for a day, if necessary.
While this is 100% opinion based, here's my 2 cents:
Yes, there are plenty of things to do, enough for a week at least. You can visit museums including MAC, Pointe-à-calière, science center, etc. You can hang out downtown or simply walk around. Usually, there will be some event or festival going on as well. Search online a bit and you will find something.
If you're into hiking, plan a trip to Mt-St-Hilaire on the south shore.