I’ve poked around there on CB500Xs with street tires, and the red GPS tracks show the routes I took. If I rode them without turning around, then anyone can!
The blue track above, from a friend, is a 4x4 road that is being widened and concreted. Construction started in 2024. I don’t know when the concreting will be finished enough for street bikes.
The 1099-3054 is a great ride, with narrow and steep but mostly well-paved hills. The biggest risk on the 3054 isn’t steep hills but curves with limited visibility. Any bike can do the ride, even cruisers, but a bike with wide panniers might not be able to fit around an aggressive Hilux coming down a steep blind curve in the center of the road that is barely wide enough for two cars. Fortunately traffic is light.
The village of Omkoi (purple circle) is a pleasant place to stay overnight on the highway. The Waranya Resort at 17.807405,98.371339 is good. Call Pieter on 064-558-8653 to reserve. I’ve stayed there four times in five years and every time had the place to myself and a long chat with the owner, but sometimes bike groups come through and then he’s full.
The elevation is about 1000m, so refreshingly cool after the sun goes down, and in the morning.