as far as i Know there are no security issues in the northern areas except in Chilas and its southern neighboiur in NWFP Kohistan. Gilgiy, Hunza, Skardu region havd never really had security issues exceopt the occasional sectarian clashes.
Hunza is quite liberal and you and your wife can dress more freely there than in other montane resorts in Pakistan. the people are far more tolerant and you will see a complete contrast between shia-sunni dominated gilgit and hunza - the absence of women in the former.
the people in these regions are very polite and the ebst mannered comapred to other hill station areas.
the KKH passes through Swat, although its far eastern portion - you should know Besham is in Swat but I think that area is realtively peaceful. Besham is a part of Swat but geographically it does notbelong there.
if you goto karimabad do check Cafe De Hunza, amazing treats there :P