Parc La Fontaine is the Plateau's lung, and Avenue du Mont-Royal is its loud beating heart, and the best afternoon in the neighbourhood is the one that does both. Four kilometres: green first, then the avenue, with the leafy residential streets as the seam between them.
Start at the park's southern gate and don't aim for anything — pick a path and let it carry you toward the two linked ponds, joined by a small waterfall and a footbridge, willows leaning over the water, rowboats in summer and skaters in winter. Loop the ponds slowly. The Théâtre de Verdure, the open-air stage in the northwest, is worth the detour even when it's empty; the grass banking is the quietest seat in the Plateau.
Leave at the northwest corner onto Avenue du Mont-Royal — cafés, record shops, terrasses on the sidewalk all summer. Pick one and watch the street. Then duck onto the cross streets, Rue Marquette or Rue Garnier, for the painted triplexes under big trees, the avenue's quiet counterweight. End back on the avenue at Mont-Royal station, one more pastry for the metro.