It looks like a fantastic spot to camp, and a positive experience with your son to remember for a long time.

During my travels in Asia, I have only ever stealth camped or stayed in flea bag guest houses. It can be very difficult knowing what is on the road ahead in terms of places to stay and places to re-supply - particularly in rural and semi-rural area.

On a longer tour in less populated areas, I would recommend looking for accommodation a couple of hours before dark. If it's dark at 6pm, start looking around 4pm. If you find something right away and the price/location is good, have an early night. If not, keep going; you'll have a buffer without leaving it until it's almost dark.