Really depends on your idea of "economical stopovers"...How much does Shangrila Hotel Chilas costs? I am not sure it is a budget hotel.
@yasirrafiq7234
This time of the year, you can get good, reasonable rooms (not luxury but OK for family) at Rs. 1,500 - 2,000 per night.
My suggestions would be slightly different to those of HanifBhatti.
Day 1 : Islamabad to Naran (or even beyond, say Battakundi or Jalkhad). There are many hotels en route and cheaper than in Naran. Else, in Naran, go to Jheel road and there are cheap options. We stayed at Rs. 1000 per night in first week of September last year.
Day 2: Jalkhad to Karimabad. Karimabad is the capital and a popular town to add to your "seen" list. Costly hotels here and they do not often negotiate much if at all.
Day 3: Go to Khunjerab pass, spend some time en route at Attabad lake and back to Passu. Stay at Passu Tourist Lodge (approx. 1500-2000 per night). You need to negotiate slightly or look for other hotels nearby like Passu Ambassador etc. If some hotel has foreign tourists usually en route or returning from Shimshal, they will cost more. Move on to the next one that is empty and they will negotiate). Passu is really calm, serene and you wake up to the gorgeous Passu Cones. Really enjoyable if you like quiteness.
Day 4: Either back via Naran side as before or if you need to take KKH then in Besham (PTDC).
Of all these places, Karimabad and Besham is where you will find the more expensive rooms. If you want to make it in 3 nights, then day 1 at Chilas, day 2 visit Khunjerab pass and back to Sost. Day 3 at Jalkhad and day 4 to Islamabad.
Important Tip:
The worst part of the journal will be from Islamabad till Mansehra or even Balakot. Try to leave very early in the morning (around 3.30 or 4 am) so you clear the congestion between Havelian till Mansehra with ease. Otherwise, it is tiresome, irritating, and will cause loss of time.
Fill up in GB instead of Naran (except at PSO if they have fuel). There is a station at Chilas, Lots of stations near the intersection of Gilgit-Hunza road, then near Karimabad and one at SOST.