Does any prepaid SIM work in Jammu & Kashmir for outside J&K State users?

You may have already completed your journey by now, but for the benefit of others who are looking for an answer to this question, allow me to respond.

Any Prepaid connection bought from anywhere in India will not work in J&K. (except local prepaid connection bought in J&K)

All Postpaid connections bought from anywhere in India will work in J&K.

J&K currently has the following telecom operators:

1. BSNL
2. Airtel
3. Aircel
4. Reliance

So, if you have a Vodafone connection for example, once in J&K, you phone will roam on one of the above service providers under an agreement by Vodafone and one of them.

I hope this was helpful.

Yes, it is too late to reply on this. However, above member (Amit Mehta) has given prompt reply on this. It is something strange from Government of India and State Government of Kashmir on this issue due to various internal security issue, most probably.

However, it is little awkward for the common Indian who used to travel to Jammu and Kashmir with their prepaid SIM mobile and suffers from tower connectivity issue or no calls allowed. The one who stay for a holiday has to either arrange Post paid SIM in advance or stay with no signal for their pre-paid SIM and use a local land phone for outgoing and incoming calls.

Its very late to reply but anyone needs to be updated on the current status will be that, as of now, in August 2017, still it is the same. Any prepaid connection we buy from outside J&K will not work here and any prepaid connection we buy from J&K will not work outside J&K, but there are no issues with postpaid connections.

And the current operators in J&K are:
Airtel
Aircel
Bsnl
Vodafone
Jio
Reliance
Idea