My experience in Muine as such. Travelled solo so stayed at a budget hotel just walking distance from the Sinh Tourist bus stop.
Noticed the hotel owner has a young daughter, chatted her up immediately. Mentioned that I may need to hire a xe om to take me to the sand dunes around 5am next morning... sunrise there is best. She said, don't waste money, she can take me there. Delighted with her offer and she took me there early next morning.
After that we went to the Fairy Springs, another local attraction. Quite nice to wade in the river and see the rock formations, like a mini Grand Canyon. Wear slippers as u will be getting your feet wet. After that we had brunch by the beach at one of the local restaurants that only locals go to. I only had one night and one day in Muine, so checked out after lunch and continued my journey. Later she messaged me asking if I wanna take her away from Muine but I was already in the bus ....