Citizens of India are lucky that they need not pay the daily tourist tariff of US $250/night and moreover they can enjoy the luxury of travelling on their own, rather than through an expensive travel agent. But, the immigration rules are different from other countries. Remember this is only for Indians.
Entry Into Bhutan
India has three entry points into Bhutan through road one each at Phuentsholing, Gelephu (maybe used only for exit) and Samdrup Jongkhar. The best option is to use the primary route that is through Phuentsholing. Phuentsholing shares neighborhood with the town of Jaigaon on the Indian side. You could just cross the border on foot from Jaigaon through an official entry point.You do not need any permits to enter the Phuentsholing.
Extending your permit and getting special entry permits
If you want to extend your permit or get special entry permit to the other districts of Bhutan, you need to apply for such permits at the Immigration Office in Thimphu. If you want to get special permits for entering the other districts of Bhutan, you need to write your whole itinerary on a paper and submit it along with the respective form and photocopy of your earlier permit.
All Indian nationals visiting Bhutan does not require visa to enter Bhutan. However, they MUST produce any of the following identity documents:
A. A Valid Indian Passport
B. Election ID card or Voter ID
C. For children below the age of 12 years, following documents are required.
(i) Original Birth Certificate in English
(ii) If the birth certificate is in local language or Hindi, it has to be translated into English and notarized by a magistrate.
N.B. An Indian citizen must be in possession of a valid passport when entering from a place other than India and when exiting from Bhutan to a place other than India.