Make one day trip from Rishikesh to Dehradun, or just stay in Dehradun for one night. In general, Dehradun is very dirty, noisy, and not too interesting city. However, something is nice to see there.
And, it’s Mindrolling Buddhist monastery in Clement town. There is the largest stupa, peaceful land of monks, and beauty of Dehradun.
Also, FRI = Forest Research Institute is worth seeing. The institute contains six museums with forest topics, and one of it is with the oldest tree.
Beside these two main attractions, Dehradun offers to see Palka bazaar, Sikh gurdwara, and rush of the capital city of Uttarakhand.
From Dehradun, we continued our hill stations trip to the next destination call Mussoorie.