Hi Suryam, Yes you can cover Mussorie in 4k if you planned it accordingly. Few tips that might be useful. 1. Take a night Uttrakhand road way bus from Kashmere Gate Delhi to Mussorie. It will come around 250 . Travel in Night , sleep on the way by which you are saving money on the hotel.
2. By Morning you will reach Mussorie, book a dormitory /bunk bed Hostel. which will come around 200 per head or any cheap Hotel at 500 max.
3. Avoid eating at fancy places. Happy Travelling !!
For 2 person in 4k is really difficult. You will need to cut down cost on each and every thing.
Take roadways bus, book hostel/homestays for accommodation (may be a bit far from mall road), avoid restaurants for meals, walk for most part for sightseeing.
Absolutely!! Just book your roadways tickets from Delhi to Mussorie & return in advance, skip AC bus & fancy restaurants, plan for only one night stay & for sightseeing book Alto only instead of big car. Enjoy your trip.