Start from Mall road (famous for shopping), Christ Church, Ridge Rd, Lakkar Bazaar, Jakhu temple (tallest Hanuman statue) , Kala Bari temple, Army museum...this all places you can cover in one day....
Yes, you can enjoy both Kufri & Mahusa peak in the end of December though the climate in Mahusa wil be sumwhere around 8°-12° bt it's worth it..
If you want to enjoy snowfall & other snow activities like skiing,yak ride ,leave for Kufri early morn (15kms from Mall road).
while returning to Mall road , you can visit Himalayan Nature park,bird park,Amusement park & Scandal point too.
Hello Sushant, Even if you have just a day at hand to explore Shimla, you can visit various tourist spots and make the most out of your one-day Shimla trip. Some of the places that you can cover in a day are: 1. Jakhu Temple
2. The Ridge
3. Christ Church
4. Gaiety Heritage Cultural Complex
5. Kali Bari Temple
6. Annadale
7. Himachal State Museum
8. The Mall You can easily visit all these places in a day including your halt time and meal breaks. I hope you find this information useful. Thanks!