There is nothing much to see in Lansdowne. One day is sufficient to complete all tourists places. But it is less crowded and clean place compared to Mussoorie and Nainital. I found calm and green mountains in Lansdowne. I stayed in resort that was 20 km before Lansdowne.
If you want to just relax and see that nature at it’s best, head to Jibhi in Himachal. It is a perfect place to just relax. The place offers amazing landscapes. A stream flowing nearby and there is a waterfall too. You can visit Jalori pass and Bahu temple as well.
Lansdowne is for those who wants to cut their self from the city life and seeking for solitude & relax environment. This place is still pollution free and surrounded by nature wellness. Celebrating Diwali in Lansdowne is not a bad idea.
Some good accommodation available there like Rio Resort, GMVN cottages etc.
You can also check this itinerary - https://www.bizarexpedition.com/weekend5