I'm planning to visit Ninh Binh so when I saw this thread, I was excited about Ban Gioc Waterfall and Ma Pi Leng Pass. Turns out they are nowhere near each other and the waterfall is only impressive during rainy season.
Ban Gioc Waterfall and Ma Pi Leng Pass look like they are in VERY rural areas. Could you get by only speaking English? Is Mandarin spoken there? What mode of transport did you use to get there? (I assume a private car)