Thank you for your appreciation and its pleasure to be of any help for your future trips 
Where have you been all these years yaar hehe ... If you havent been there before then it will be inshallah an amazing and wonderful experience for you. I haven't been to Murree etc. in summer since i first visited Kaghan valley in 2005. If you are a nature lover then a memorable experience is guaranteed!!
Camping at Saif-ul-Muluk is really fun. AND you are lucky that your trip dates coincide with full moon dates i.e.24 or 25 July. If possible try to camp there in these dates and wait for the fairies at night 
1-The tents are available on rent at lake also but i am not sure about sleeping bags. So better please check with the guy i mentioned above in Naran and arrange your stuff from Naran as everything is available on his shop on rent.
2-However, you will have to deposit security for the things you will rent which is of course refundable once you return the equipment. So you should have some extra cash.
3-Weather will be much colder as compared to Naran and warm clothes are a must.
4-Try to get a water proof tent or atleast a plastic sheet to cover it in case of rain.
5-Try to take night shots
and visit lake early morning to enjoy the calmness and still water beauty.
6-Food is available at lake so no need to take anything from Naran.
1-Lalazar Hotel was renting out a room for 4 people on Rs.3000. Good hotel but expensive.
2-Royal Hotel also in same range.
3-Punjab Hotel. You can find a room for three around 1100 but rooms are just OK. Manageable if you only want to spend the 8-9 hours of night.
4-Sarhad Hotel. Around 1200. Rooms are in better condition.
5-Another hotel which we checked but unfortunately rooms were not available is in the street just going in opposite to Sarhad hotel. The front of the hotel is under construction but the rooms are extraordinary for the rent of 1200. Do check that out.
Others were all asking between 1500-2500 so i dont even remember the names.