Some villages with gas stations. Only few bigger town called. Awesome viewpoints over the jungle and lot of corners. Only problem of the road is surface. Mostly it is panel road with some small stones on the side, which are often in the middle of road in corners. Also be aware of dogs, cows, buffaloes and their excrements. It´s hard to find place to sleep in the villages. I meet few westerns travelling with hammocks, what can be solution if you don´t like searching for home stay.
First half closer to Hue have some traffic there, but I didn´t meet anybody on the road in last 1.5h of riding before Phong Nha. There is also no signal there