During the good old times when I was a student, I did not have the luxury of flying to Guwahati from my hometown Silchar whenever I wanted to or had to.
With a very slow train that took more than a day and half to reach Guwahati from Silchar as an alternative to flying, the only feasible option was the (actually it still is, until the BG becomes operational) overnight bus service which took ~12 hours to make this journey.
The reason behind this journey taking much less time than the train route was, unlike the longer train route which passes through the hills of North Cachar (Dima Hasao now), the buses take the shorter route through the National Highway 44 which snakes through the beautiful hills of Meghalaya.
Almost 75 percent of this road lies in the hill state of Meghalaya. From the Silchar side, only the initial 40 kilometers or so, with green tea plantations on both sides of the road, is in Assam.
Same is the case on the other side as well. The road enters Assam just ~35 kilometers before Guwahati at the border town of Jorabat. Rest of the route is in Meghalaya, passing through small and big towns and cities like Umling, Umkiang, Jowai and the capital city of Shillong, etc.
This route is one of the many picturesque ones in the north-east. And even with all the landslides and traffic jams during the monsoon season, to me, this route is amazing when done during the monsoons.
PS.- Please excuse the quality of the photos as these are almost a decade old when I barely knew how to hold a camera.