Visit Three Pagodas Pass and the border market and, if the border's open, cross over to Payathonzu, on the Myanmar side of the border. The road out to Three Pagodas Pass passes a side-road to a waterfall. To reach the waterfall, you must walk through the jungle and cross rivers, sometimes by swimming at least in the rainy season. There is another side-road to Wang Bandan cave.
Stroll around town, go for a swim in the lake, relax, enjoy the sunrises and sunsets.