Siliguri to Border town of Jaigaon / Phuentsholing is about 150 Kms or so and takes about 4-5 hours of leisurely drive. The route is Siliguri to Gangtok NH10. take a diversion at Sevoke (about 24-26 kms from Siliguri) to right over the bridge on river Teesta and then it is via Damdim-Mal Bazar – Nagrakatta – Banarhat – Binnaguri – Birpara – Madhya Madarihat – Hasimara – Jaigaon. The roads are good with moderate seasonal traffic and should not be an issue. There is a Bhutan riders club there called Bhutan Dragons and Mr. Tshering & Mr. Thinley Wangchuk are awesome guys and helpful if any assistance is needed