Thanks for the report and pics, as Ray said a road that us Isaarn guys enjoy a lot.
When you get to Ubonrat, instead of going East to the No 2 highway, there is a newly surfaced road that is not on your map, it follows the Eastern side of the lake, down south until it hits the no 12 about 20km out of Khon Kaen. This road is great, some enjoyable bends, ups and downs, all accompanied by glorious scenery, Ok it does not have the grandeur of the higher parts, but its the best bendy road in this part of the country.
Avoid it late in the day when the cows are changing pasture.