Pope John Paul II offers the first thought on this:
142. Each community is called to create a “God-enlightened space in which to experience the hidden presence of the risen Lord”. [Vita Consecrata 42]
Scripture and sacraments help us toward sanctity:
Sharing the word and celebrating the Eucharist together fosters fraternity and makes us a holy and missionary community.
When Pope Francis speaks of mystical experiences, he could be including popular piety, but I suspect he is also thinking of a guided spiritual life. Likely his own Jesuit experiences with imagination in prayer. Not only can we create spaces for community sharing, but the encouragement is also needed. Pope Francis mentions Monica and her son, but don’t forget married couples, work groups, families, committees, etc.:
It also gives rise to authentic and shared mystical experiences. Such was the case with Saints Benedict and Scholastica. We can also think of the sublime spiritual experience shared by Saint Augustine and his mother, Saint Monica. “As the day now approached on which she was to depart this life, a day known to you but not to us, it came about, as I believe by your secret arrangement, that she and I stood alone leaning in a window that looked onto a garden… We opened wide our hearts to drink in the streams of your fountain, the source of life that is in you… And as we spoke of that wisdom and strained after it, we touched it in some measure by the impetus of our hearts… eternal life might be like that one moment of knowledge which we now sighed after”. [Confessiones, IX, 10, 23-25: PL 32, 773-775]
You can check the full document Gaudete et Exsultate on the Vatican website.