As a very old road tripper, (I have experience of 6 Himalayan Road Trips, 1 Rajasthan, 1 Kerala and countless goa trips.) would like to congratulate and suggest you for Himalayan road trip. Start early, retire early. No ego on road. Avoid Non-Veg on the run are few essentials. While preparing for Himalaya, do go through series of road trip books by Mr. Koko Singh (Rupa Publishers). Road Map by Nest and Wings are must in Himalaya. All the Best !!
