Please read my post from another thread:
I used to take my babies (few months old) to northern areas, now they are 4/5.5/7 years old and going 3/4 times a year since they were few months old. Even did winter trips.
We went till Khunjerab border and on our way back used to come direct from Gilgit to Lahore in 18 hours continuous drive.
Alhamdulillah they are brave, bold and stronger than kids of their age.
As suggested by @mehran you should carry bottled water with you and never use water of local area for the child. Water must be lukewarm.
Get a good quality thermos which keeps liquid hot for upto 24 hours, and a 12v electric kettle/mug to use in car as in those areas power will not be sufficient to use 220v kettles as they draw upto 1500 watt.
Get bodysuits for the baby and good quality sleeping bag something like:
Carry cot is must as baby and the mother gets tired by holding in the lap, carry cot should be flat one instead of curved, so baby can sleep easily
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A front baby carrier, you will not be able to enjoy yourself without it as holding the baby and walking will kill your back
Most important thing is to take disposable scented diaper bags, please be a responsible tourist and don't throw diapers in open, you can keep used diapers in your car without any odour and dispose them in proper dustbins

Also carry wrapping sheet, medicine (like panadol, caricef syrup), mittens, woolen caps which cover ears as well.
If you don't have this stuff, buy it, as it will be best investment and will serve you for years and babies to come.
Weather is not very cold these days, so go without any fear, InshaAllah everything will be good.
Have a safe trip.
You can read some more suggestions from this thread: https://www.pakwheels.com/forums/t/travelling-with-an-infant-4-months-old/841748/19