Nehru was interested in Kashmir since 1930s, and was working on it by visiting the valley and developing his friendship with Abdullah.
The pragmatic Sardar Patel felt that India would be better off without Kashmir.
Jinnah never visited Kashmir or tried to engage with Abdullah.
Technically Gurdaspur should have gone to Pakistan as it had 55% Muslims, 30% Sikh and 15% Hindu population.
- Nehru’s letter to Patel (September 27th, 1947), three days before Kashmir’s accession to India
The Indian Army in 1948 under Major General KS Thimayya was over stretched and was under serious danger of getting out flanked, if they had pushed forward to retake Gilgit & Baltistan.
If you get outflanked while conquering a mountainous region, you are basically F8cked. Indian politicians should read some Military History