Hi shruti There are two approaches ... you want to be in a crowded place or you guys are looking for ME time. If you want to be surrounded with people then mussoorie is good option for you and followed by Dhanuati. If you want a me time ... which i think is more likely.. you should divert you destination from mussoorie to kanatal. its above dhanaulti. It's a beautiful small town with a perfect blend of good hotel options and late back culture. You can go for small treks , village tours and also combine chamba and dhanaulti. You can also explore botanical garden in dhanaulti. Your can make this trip budget or luxury as per your desire. It fits into all pocket size trips.
Hotel option in kanatal - Go for hermitage ( my favorite ), mahindra club and can check in airbnb as well.
If you are a chinese food lover ,please halt at dehradun for one meal at orchid( both food and ambience is mind blowing)
Hi Shruti, I suggest you to make a detailed itinerary for your 4 days from your start day.
From Delhi, you can visit Dehradun first. Explore the city and then can go for Hrishikesh trip for a peace tour. Once done I recommend you to book your stay for 2 days at Mussorie to enjoy your final stay at hillstation.
For complete itinerary with hotels you can consult me.
Hope you have a good stay with your family!!! 😊