Hi Harsh, Some good places to visit in Bhutan are - Dumtse Lhakhang, Phobjikha Valley, Lheunste, Haa, Kila Nunnery, Philatelic Bureau, Paro Taktsang, the Lama Tshering Dorji General Shop and National Handloom Development Project in Trashigang. For a more detailed itinerary, go through this - https://www.tripoto.com/trip/kolkata-jaigaon-paro-thimpu-wangdue-56b0f1284ab73
Well my friend you have chosen the best place to be. I have also planned to land to Bhutan later this year. Hire a local cab, stay in Thimpu 2 days, 2days in Paro & one day in Punakha. You dont have to worry about anything the local driver will cover everything. Just dont forget to do the famous Tiger Nest trekking in Paro, that will take one full day of yours & also visit the Punakha Dzong.