From Maputo head toward namacha. Shortly after passing Boane you will make a left turn and see a ridge rising up in front of you. At the top of this ridge you can head either left or right on foot or if you are adventurous with your car. It's a short hike from the main road to good cliffs and some really fun climbs. From Namacha head towards Maputo. You will descend into a valley and then pass a rock quarry on your way up the noticable ridge. At the top head left or right.
I have never experienced any red tap and no one has ever cared that we were climbing here. That said it is Mozambique and hassels can and do tend to appear out of thin air.
You could easily pitch a tent on the fairly level round on top of the ridge but that would mean a big hike to get water.