It's great to finally see some people who know what good roads are- not "daily commute" runs.
My personal favorite is the road that runs from Pindi Cantt through Dhamial Air Base and goes to the Chakri M2 exit. Minimal traffic as soon as you get out of the village areas, low pedestrian traffic, and GREAT curves. Elevation changes make for a really really great drive. It may not be the fastest way to get onto the M2, but it's definitely a fun way!