Salam Adrian and Syzygy,
I'm a Northern Areas fan as well, and I've been there almost every year since 2001 But I've only been to Hunza once in 2001 and I didn't read/research much because every name and every place was new for me. I was reading a couple of books that mention that Altit and Baltit are villages in Hunza Valley (like Karimabad is the main town in Hunza Valley). The forts also take the name from the villages. In one book they were mentioned as "Mirs' palace at Baltit" or something like that, it was probably later that they were called as "Forts".

I've recently bought this book "Pakistan Trekking Guide" by Isobel and Ben Shaw (a mother-and-son team of trekkers who explored Pakistan in 70's and 80's). The book is very well-written, and the edition I've got is 1993's revision, the only issue is that the prices it mentions have actually been doubled or tripled since then, otherwise, it has some 50+ treks and some 50+ detailed maps of all the Northern Pakistan (from Chitral to Swat and Ishkoman, Yasin to Shimshal and Khunjerab).

Isobel and Ben Shaw have written other books as well, and I guess they'
re as good as this one, but this book is like the "official" trekking guide for Pakistan

Also, I've been placemarking the Northern Pakistan in the last couple of weeks, here's what I've got so far:
http://bbs.keyhole.com/ubb/showflat.php/Cat/0/Number/420123/an//page//vc/1

I like the Baltit Fort pic, you've placed it in the perfect orientation!! I've got your overlays as well and will use them for more placemarks.

Thanks!