This might be helpful. Source:
http://iguide.travel/Islamabad/Walking_In_The_Margella_Hills
The Margalla Hills are effectively foothills of the Himalayas – and are very easily accessible from Islamabad. However these are quite big, steep hills, and shouldn’t be underestimated – if you are planning on a walk up to the top of the first ridge (ie where the Monal restaurant is) then sturdy footwear, a large water bottle, and a change of t-shirt are necessary (good chance you’ll be drenched in sweat by the time you get to the top). Between March and November it is best to start walking in the early morning (before 7.30am, or 6.30am in the height of summer) as it is uncomfortably hot during the day.
There are many trails to choose from, some of which have been numbered by the city planners. The more popular walks are Trail 3, Trail 5 and the Zoo Trail. Google Earth gives a good way to orientate yourself before you set out.
Trail 1 – also known at the E7 or Faisal Mosque trail. Little used, in part because it is so difficult to find the trailhead. Head to the carpark to the rear of the Faisal Mosque, and look for a gate with a Margalla Tree Planing Project sign next to it. Head through the gate, take the first right, then right again (at a grey concrete box) through a small clearing, and turn left at the end. Walk north toward a large concrete water storage tank, and walk to the right of this on to a well defined path (GPS coordinates 33.734112° , 73.038421°) from here it should be plain sailing. Trail 1 winds its way up to the ridge, where you can turn right and reach the Pir Sohawa road, near the turn-off for Talhaar. Takes about 2 hours to get to the top. From Pir Sohawa road its a 20 minute walk to the Monal restaurant, and you can catch a taxi back in to town, or head down Trail 3 or the Saidpur village trail.
Trail 2 / Zoo trail – Trail 2 begins a little way up Pir Sohawa (just past the Jungle Shack drinks bar – GPS 33.7346° , 73.0545°) or you can start from the right of the entrance of the Islamabad Zoo. This is a good choice if you are looking for a 1-2 hour walk – the trail leads up to the Daman-e Koh viewpoint – if you want to continue walking a trail up to Cactus Ridge leads from next to the Police checkpoint near the entrance to Daman-e Koh. From Cactus Ridge you get a good view of where AirBlue flight 202 crashed.
Trail 3 - begins from Margalla Road, F-6/3 (the junction between Margalla Road & Ataturk Avenue). It is a little steep and strenuous in the first leg, which goes up to the Viewpoint and is about a 30 - 50 min. trek. After the Viewpoint you can continue on for another easy-going 45 - 60 mins and reach the Pir Sohawa, where you can choose from 3 restaurants for food, The Monal, Treehouse and Capital View Restaurant. This is the most popular walk, hence litter levels are high.
Trail 4 – this is a link trail between Trails 3 and 5
Trail 5 also begins from Margalla Road in F-5 (about 500m down from Trail 3 - opposite Judge's Enclave) and is initially an easier trail to climb. Trail 5 connects with Trail 3 (via Trail 4) and meets beyond Trail 3's viewpoint. If you continue on Trail 5 you eventually meet the Pir Sohawa road (33.7675°, 73.0771°) although it is possible to get lost on Trail 5 and veer too far east. Don’t try Trail 5 without a GPS or a friend who has done it before. From the top of Trail 5 it is 1.5km to the top of Trail 3 – hence you can do a loop, taking 3 – 4 hours.
Siadpur trail - follow the river through the village (including ducking though some back alleys) and you'll emerge in a valley and a trail that leads up to the Monal restaurant - and hence you can easily do a loop coming down Trail 3. Siadpur trail isn't much used so it largely free of litter.
Bari Imam trail – for the more adventurous this is a good hike. Drive to Nurpur Shahan (east of the government complexs beyond the end of Margalla Road) – head to a road junction at 33.7457°, 73.1050° and turn left, until you reach a turnoff for a small guesthouse at the start of the trail (33.7569°, 73.1135°). The walk starts with steps leading up to the Bari Imam cave, then you can continue up the steep hill behind, then traverse round to the Pir Sohawa road, where there are a few cafes and a hotel (33.7843° , 73.1107° – it is about 5km from here to the Top of Trail 3 if you follow the road). You can return down the valley back to your starting point. Beware however that you pass into Khyber Paktunkwa on the walk and you may have to charm yourself pass some policemen.
Both Trail 3 & Trail 5 have large maps and guidance boards placed at the entrance
