Phu Thap Boek (1,794m) is the highest point in Phetchabun province and home to one of Thailand's most savage climbs — 111 bends gaining well over a kilometre of altitude on gradients that punish a lazy gear choice. The summit is a different world: Hmong farming villages, cabbage terraces draped over every slope, and a sea of mist below at dawn. Ride it as an out-and-back from Lom Sak; the descent is a masterclass in engine braking.
Clone it to your planner, customize dates and stops, then ride. All free.