Vietnam is probably the cheapest place on the planet to travel to, bus or fly about; I think that's because of the Dong, valued at 20,000:1 (Dong:USD), which can also cause nightmares at ATMs when literally thousands of notes of Dong are spewed out for something like a $50 withdrawal!! It was not cheap for us in 2003; things have changed hugely in a decade. Maybe seek out items of interest at Angkor wat (Hindu/Buddhist) in evening or morning light — it is hauntingly beautiful, if so well-known as a tourist trap that you will be standing in millions of previous footsteps and probably won't get something that none of the rest of the inquisitive world has seen before you. The most remote areas of Vietnam are probably best done (safety and local knowlege) with a guide (our own tour was with an Australian-based company at the time which was taken over by APT some years ago). I can't imagine finding any really accessible wilderness/undiscovered areas close to cities because so many photographers do visit Vietnam with the same ideals! If we go again and I photograph Ha Long Bay, I'd first hope to get rid of all those tourist junk boats cluttering the scene — they really are prolific and pesky.