This mountain is a little short of being 8000 meters but is the most technical and gorgeous peak in the Gasherbrum Group. The famous 'shining wall' was first climbed by Walter Bonatti.
From Rawalpindi catch a bus to Skardu OR fly from Islamabad to Skardu. From Skardu get a private jeep hire which will take you to Askoli village. From Askoli you follow a "trail" through the Braldu valley and onto the Baltoro Glacier. You can get to Concordia in about a week. From Concordia the basecamp to G4 is about a 5-6 hour hike.