I went to Lake Kallar Kahar a while ago over the weekend with my wife, on a friend's recommendation. I was very disappointed by the experience. It is situated about 350 kilometers from Lahore on the Lahore Islamabad motorway. We boated in the lake full of dirty water. It wasnt worth all the travel. We wanted to touch Khewra mines, too, but scrapped the idea.
CNG stations along the way were low on pressure and I drove consider amount of the time on petrol. My recommendation, dont go there.