About 30 minutes after leaving Pai, we reached Kiew Lom viewpoint which is the highest point on the highway to Mae Hong Son, which is at about 1400 metres elevation. We got there at about 8:00 am, and it was a good time for photos with the sun still low in the sky and blue sky with the clouds below. Looking at some of the "Facebook photo check-ins" from other travellers along this road, it seems this point is quite often in the clouds with not much to see, so we got lucky here.
Tham Lot is a cave just off the road and about half way in between Pai and Mae Hong Son. Tham Lot cave has river flowing it, and the easiest way to see it is to float downstream on a bamboo raft. The way back up against the current is slightly more difficult.