I am on a week long vacation to India and specifically want to explore Himalayan state of Himachal Pradesh. How should I plan my trip ? 
 Firstly , fly to Delhi or Chandigarh. These cities are well connected via flights from across the world.  Next , take an overnight bus to Manali.  There are ample buses available connecting Manali from any cities.  Spend 4 days of your time  enjoying local cuisine and sight seeing.   Do carry wollens  as temperature drops sub zero during the night. Next , head towards Shimla and spend 2 days here for local sightseeing enjoying marvels of British architectures and old mall road.  Wrap up your trip travelling back to Delhi or Chandigarh. Spend time doing some local shopping before you fly back home.