I would recommend visiting:
1. Sumendu Lake. This is the perfect place for boating, with just the right environment and serenity as well. It also has an arched bridge perfect for lovers.;p
2. Bokar Monastery. This is located at the highest spot in Mirik Town. Tourists love watching the sunrise and sunset here.
3. Orange Orchards. What's more beautiful than seeing oranges after oranges after oranges?
Enjoy!