Hi Abhiram, We hired a car from Jaigaon for the complete trip. That is a good option for a couple or a family. But for renting bikes, you can certainly check in Jaigaon. I saw lot of bikers coming to Bhutan but on their own bikes. How do you plan to reach Thimphu?
I visited Bhutan last year and me and my friends rented a car outside the Immigration Office in Phuentsholing and we really got a great deal. For a total trip of 5 days we paid him INR 15000 and he dropped us off at the Hasimara Railway Station. Also, there were a lot of bikers from India on their own bikes. Hope this helps.
Are you going solo or in a group? I have been to Bhutan in October 2019.Can give you suggestions if you inform as to how you plan to reach Thimpu.I had served in Bhutan in nineties briefly.Regarding bikes,I will find out and let you know.
Notice you are going in a group of 6 or 8.It is going to be cold in January.My suggestion is that you hire a car.I can put you in touch with a Bhutanese friend who will be of great help to you.He can pick you up from Phuntsholing.Since you are going a long way,my suggestion is that you visit other places also.For instance,Punakha and Paro.Rest is up to you.