I stayed at army guest house, my brother in law is in army and posted at Mangla, otherwise most of people do it as day trip because Mangla is easily accessible from Lahore or Islamabad as day trip. I think there is no restriction on entry of civilians unaccompanied bt army personal .However at gate they will keep your ID card and issue you a chit which you deposit on way back and get your ID. They security check post people also ask for a driving license. The charges for army people are half of what civilians are charged.
