Hi Shiamak, that's really an amazing adventure to pursue with your friends!
I would be suggesting you a route on the basis of accommodation, accessibility through Ladakh. 1. Chandigarh - Manali (via Bilaspur, Kulu valley & Mandi) 2. Manali – Keylong - Sarchu (refuel at Tandi, which is the last petrol station before Leh) 3. Sarchu – Leh via Gata Loops & Moore Plains 4. Reach Leh and Rest 5. Leh – Changla – Tangste – Pangong Lake 6. Pangong to Hunder Via Shyok or Wari la or Agam 7. Leh – Lamayuru - Kargil Optional : Kargil – Drass – Sonmarg via Zoji La Pass and Depart from Srinagar.