Go down where the rivers meet at sunset. Also book a boat ride out to the caves late in the day so you're returning around sunset.
There's some waterfalls that are nice. You can book cheap trips to them on the main street. There's also a market on that street at night kind of a touristy thing and then there's the real locals market during the day that has everything under the sun. That's a little further out.
Of course all tourist turn up before sunrise for the monks. You won't believe how crowded it is. Get a shot or two with them walking by some of the temples and then go to the back and side streets where there's almost no tourist. The monks walk a circular route back to their place, if you're there a couple of days you'll figure out who goes where. Also hang around the temples when they get back and you'll see them doing everyday stuff, washing dishes, cooking breakfast, etc.
There's a footbridge across the smaller river that may or may not be there depending on how big the flood was, have they rebuilt it yet, etc. but if so there will be some shots to be had.
