Hi, I went to Nag Tibba in Uttarakhand some time back. You can reach there trekking, which in itself is not very difficult. Once there, you will find the most beautiful views of the Himalayas. Also, the place where we camped overnight was after the last village in that area, and had the smell of mint everywhere. It was just us and the guides (2 guides plus cook plus luggage helper who came with a horse for the luggage).
There are many hidden beaches and mountains in india where very less people seem to travel mainly the beaches in odisha, west bengal like talasari beach and in the north east which have plethora of amazing scenery and is still unexplored..
'India is really an underrated country when it comes to see the nature's beauty. But you cannot expect to travel for 300 kms and expect a scenic view. I have experience it myself and have written about my experiences as well. I have seen the snow-cladded mountains, I have trekked for hours and hours to reach a hilltop. and I tell you, all of these efforts are worth it and given an opportunity, I would do it all over again and again.
Its depend on when you are going and in which season. Nowadays mainly Hill stations are fully crowded due to summer season started. After rainy season mostly Kerala, Munnar, Pune, Gangtok will be good place. In October you can visit Pondicherry, Goa also.
Crowd depends on seasons. In summer usually hill stations are very much crowded places. Post summer places like Ooty, Munnar, Chikmangaluru, Kodaikanal are best spots with mind blowing greenery and chilling climate. It will be peaceful trips. Refer my blog if you would like to know more about Ooty ( Nilgiris) - Queen of Hill Stations.
The places which I would like to suggest you is Chitkul and Kalpa in Kinnaur district of Himachal Pradesh. These are not very hard to find but surely are hard to reach as you will have to cross one of the most dangerous road in India i.e. Kinnaur road. As it has narrow road carved out of rocks with some sharp blind turns. Both these places have mesmerizing scenic beauty covered with snow. And the good thing is that these are not commercial places so you can sit, relax and enjoy the nature. The place is nearly 10-12 hours drive from Shimla.
India offers a variety of travel experiences, in the past decade the number of travel enthusiasts have been increased. So I would suggest you to first choose where you wanna go, to the mountains or to the beaches or to the monuments. Then I would suggest that you research a bit on it, you may find something interesting which many people usually neglect plus if you ask for some hidden points of a specific position you might get an answer which you are looking for.