Ex-Gangtok - Tshangu Lake visit and Baba Mandir excursion
You go on an excursion to the Baba Mandir, the Tshangu Lake, one of the high-altitude lakes and more. If you want to, as an optional visit, you can visit the Nathu-la Pass along the Indo-Tibetan Border (closed on Mondays and Tuesdays).
It is worth a visit, as the scenic landscapes will mesmerize you. The will definitely be strenuous, and it can be an adventurous too.
Or
You can opt for a relaxed, leisurely visit to the Rumtek Monastery (if you didn’t get to visit on the day you arrived), the Enchey Monastery, local temples, and View Points. Both of these excursions will take till early evening.
After which, you have the rest of the day on leisure. You can choose to visit local markets, go shopping or just relax.