From the Wall you can see a mass of plane trees on the edge of Girona, which you pass if you enter the city from the north by car. This is 'La Devesa' Wood, meaning land used for grazing and collecting firewood. This wood, some of the trees planted by Napoleon's soldiers on their occupation of the city between 1809 and 1814, is where the 'attracions' or fair ground is and where the summer and fiestas 'carpes' are - open-air bars with music. These open at night til late. During the day they are used for 'health walks' and jogging and there is the municipal outdoor pool. There is a ltitle route to follow within the 40 hectares of wood.
From Plaça Independencia walk away from the river (Onyar)to where the taxis are lined up outside the post office. Keep heading in the same direction and you'll see them in front of you.
From the train and bus stations, turn left as you leave and continue for 10 minutes to the end of the road. Again, you'll see them in front of you but you might have to pass some roasted chestnut stands, on the way....
From the apartment, the pool is a 13 minute walk, just long enough to work up a sweat... Take a picnic.