First of no offense is intended I am just trying to be practical keeping in view my own physical capabilities,
I am giving below approximate altitudes of main stations for the intended route
Balakot to Lulusar is about 132 km
I bike for about 15km every 2nd day on flat surface (like Shiekhupura) in front of sea thats 0 m and try to find routes with occasional hikes of 5 to 10m in a distance of about 2 to 3 km and it makes me feel like I am not yet ready for uphill biking of Kaghan valley, It is hell difficult pedaling head on in the wind on flat surfaces what to talk of uphill.
All that I am trying to say is that if you can ride 20km in salt range or some other nearby mountain range comfortably then good for you otherwise it would be more like taking your bike for a walk uphill.
Should be able train myself till Apr May my intended route was Neelum valley > Shontar Pass > Astore > KKH > Chillas > Babusar Pass > Kaghan Valley but due to security issues in Kohistani areas trying to chart a new route (some sections would require carrying bike on shoulder)
best of luck