Take a bus to Coochbehar. It will take 6-7 hours. After that take another bus to Jaigaon from Coochbehar. It will take 2-3 hours. From Jaigaon cross the border gate and reach Phuentsholing and do nec (Read More)essary documentation at Immigration office. After that take taxi or coaster bus to Thimphu which will take another 6-7 hours.