Pakistani travelling to Indian Kashmir?

There is no blanket ban on Pakistani nationals for visiting J&K. When a visa is issued to a Pakistani national for visiting India their visa specifies the cities/towns they are allowed to go. You may or may not get permission to visit Kashmir but to find out you would have to apply for a visa and in your application you need to mention where all you want to go in Kashmir and your purpose. If your reasons are good enough then I don't see why you wont be given a permissions. Indian embassies are there to provide visas for genuine visitors and they have no interest in preventing people from visiting certain parts of the country provided you can make them believe that your reasons are genuine and you intend to return back to your country after the visit within the permitted time frame.

Many Pakistanis visit Kashmir. But usually they are Paksitanis with relatives in Kashmir - e.g. attending a family wedding. There is a huge diaspora of Kashmiris in Pakistan who still maintain ties with relatives in the Indian administered Kashmir Valley.

But the visa can take a long time as India treats the visa applications of Pakistanis with extra scrutiny. This additional scrutiny even extends to people of Pakistani origin with European or US passports - because the form asks where your parents were born.
So if one of your parents was born in Pakistan you are automatically treated with the same scrutiny as a Pakistani citizen.

In my experience, if you have an invite from a relative or someone influential in Kashmir, you can get the visa as quick as a couple of weeks.
But if you are just going as a tourist it can take as long as six months (and of course you may get a rejection or no response at all) and they might even want to interview you.
From experience, the reverse process of a Kashmiri visiting Pakistan getting a visa is relatively easy and quick.
But in both cases (a Pak visitor to Kashmir, or a Kashmiri visitor to Pak), you have to register with the local police as a "foreigner". They say this is for your own protection.

One of the earlier comments was that "according to immigration laws of India, the Pakistani citizens are not permitted to visit Kashmir" - if that is the case then it does not seem to be enforced as I know many Pakistani citizens who visit Kashmir annually to see family.