Originally Posted by Yaatri

India is too large with disprate climates in different parts of the country that it's impossible give one ideal time of the year.
Two weeks is too short a time to cover the list, unless you are on touch and go schedule.
You will have to be more specific with Himalayas, as these mountains stretch from the north to the east, over nearly 2000 miles.
I doubt that one travel agent can help with all of these places.