Pakistan is a failed state and cannot guarantee your security. The failure of the state is obvious in the daily news of target-killings, terrorist attacks, and kidnappings for ransom: most of these cases remain unsolved.
AVOID travel to Pakistan if you can.
BUT if you have to…
Pakistan is slightly 'safer' for travelers of Pakistani descent and others who don’t stand out as people of European descent.
If you are of Pakistani descent you are ‘safe’ in urban centers—restrict your movement and keep only close relatives and friends informed about your travel plans. Pakistani-descent people are relatively ‘safe’ traveling on train on the main N-S line (Karachi to Peshawar).
In Sind, traveling by bus or car on the east side of the Indus is slightly ‘safer’ than traveling on the west side of that river.
In Punjab (and specially north of Multan), traveling by bus during daytime should be safe. It is also ‘safe’ to travel by bus to Peshawar.
It is not safe to travel in Balochistan if you are not a Baloch or Pashtun. Even if you are Pushtun you should avoid traveling south of Quetta--it is all Allah-Nazar country where ethnic cleansing seems to be the adopted policy of the Baloch nationalists (more murders like that of Mehmood Afridi coming up soon--Punjabis and Muhajirs have been fair game for a much longer time).
Travelers of European descent
If you really, really, really have to travel to Pakistan, the ‘safest’ place to travel to is Islamabad. Fly in Islamabad, move around in Islamabad, and fly out of Islamabad.
If you are traveling to Karachi, leave the airport and reach back to it only during daytime, with good traffic on Shahra e Faisal. Ditto for Lahore. It is also relatively ‘safe’ to cross Wagah border into Pakistan and then take taxi to Lahore. Traveling on Daewoo buses in northern Punjab, during daytime should also be 'safe.' Do NOT travel in KP or Balochistan—unless you wish to financially support the Taliban or the Baloch nationalists for their respective wars, through ransom money to be paid by your relatives/government.
[This writer feels qualified to give travel advice not only because he keeps his ear to the ground, but also because has been traveling to Pakistan every year. In January 2013, he took Khyber-Mail from Karachi to Mirpur Mathelo; traveled by car from MM to Sadiqabad; took Daewoo bus from Sadiqabad to Multan; after a short stay in Multan, took another bus from Multan to Lahore. A couple of years back he flew from Karachi to Gwadar, stayed there and watched with interest Chinese engineers escorted to the airport in armored vehicle. He has also traveled on bus from Old Sabzee Mandi in Karachi to Quetta; has taken train from Quetta to Taftan (crossing into Iran); has taken a 4X4 from Taftan to Quetta. Has also flown from Karachi to Dalbadin and then taken 4X4 taxi to Taftan. He has traveled overland from Karachi to Khunjerab (crossing into China); has crossed Wagah into India by train and on foot, multiple times; there have many other trips throughout Pakistan. He once found himself stranded at the Dadu train station unable to go to Moenjo Daro because of a ‘police muqabla’, with IG Sindh surrounded by unhappy armed people. In short, he has firsthand knowledge of Pakistan’s gradual descent into chaos.]
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