For Khanjrab, you essentially require 5 Nights and 6 Days as mentioned in Post. In battakundi there are not so much develope dhotel for right now. So its better to stay in Naran(heritage hutts near saif al malook exit) Or Venus Guest House (Lalazaar Peak). Room rent will be same at both places i.e. Naran and Lalazaar (2000 per room/ night) but Lalazaaar is really natural and having low temperatures. Only thing is you need to pay jeep rent for Lalazaar (3000 for overnight). For having an really enjoyable trip, i will fully recommend stay in Lalazaar. For that you haev to pak vehicle at Lalazaar Jeep point. Contact with Driver Mir Hassan (Vehicle No 1552 Blue Colour Jeep).
ISB to Natran took us 7.5 hrs with short stay via Muazffarabad and Mansehra By Pass Road. But it also depeen dupon you are fast driver or drive with patience. Patience drive without any hurry will take 8 hrs and i will recommend patience drive. Just 1 mistake can make situation fatal in these areas.
W.r.t 3 nights and 4 Days Trip, you can follow below plan. Remember Police will not allow you to travel towards Babusar after 4PM in eveinig from either side i.e. from Naran to babusar or from Chillas to Babusar.
Day 1: ISB to Naran and Night Stay at Lalazaar
Day 2: Lalazaar to Nomal Village via Babusar and KKH, night Stay at Nulter Village (Naagri Guest House)
Day 3: Visit of Naltar Lakes and arrival at PTDC Hunza or Golden Peak Hunza by 1400 hrs. Check in at Hotel and visit Attabad Lake and back to Hotel on same day
Day 4: Hunza to Naran (Reach 0 point essentially before 4 PM). Stay at Herritahe Hutts Naran
Day 5: Naran to ISB or even on Day 4 you can directly back to ISB if you have good driver as an backup.
Drive in all areas with patience and calm. Avoid to give un necessary dippers and Horens.
For any further query, let me know.