If you only have a limited amount of time this short 4 day trek starting from Rishikesh is a great option. It’s a little longer than a half day drive to the trailhead at Sari village. It’s an easy 45 min hike to Deorital Lake which offers great views and fantastic camping. The second day takes you to Chopta and then on to the summit of Chandershila which offers fantastic views of Chaukhamba 7000m+ in the distance. The entire hike has fantastic views of the Himalayas and the high point at Chandershila is 4000m so the trek poses no acclimatization issues. If you go in April expect the hills to be colored pink from the blooming Rhododendrons.