First answer two questions.
- Would you be traveling in your own car? Which car is it?
- Are these 5 adults all male?
You will have to stop at Lahore either just to freshen up or spend nights, that's up to you. You can find many hotels there. Wait for the suggestions from Lahore guys and in the meanwhile Google some on your own as well.
If you've spent night(s) in Lahore, you can directly go to Murree. If you want to stay in Islamabad as well for a day or so, you can do it on your way back from Kaghan. In any case, you can stay in my guest house in Islamabad. I will give you my Manager's number and you can talk to him about it.
For Bhurban and Murree, just take a hotel in Murree as going to Bhurban isn't an issue. Again, you can find many in Murree. Either get an advance booking or I am sure you can get one on the spot. If you are looking for a good and well known hotel, then advance booking is fine. Else, it would be better if you can see the rooms, washroom, location etc. first before finalizing.
For Kaghan, you'll have to consult some expert for the route. If there are ladies with you, you'll have to go for the trouble free options. Advance booking should be preferred in a known hotel/guest house as availability might be an issue these days. Wait for some one who have been there to comment. Or drop a mail to Libra and he'll suggest you the hotels there.
Regards.