Trang An is 7 km west of Ninh Binh via a scenic road that many tourists decide to take on a bicycle. Once you get there, there is a temple where you can buy a boat tour. That is the best way to explore the area. It is the same boat of capacity for 2 as in Tam Coc. The tour, however, is a bit different and even if you enjoyed Tam Coc tour, there is no harm taking another one in Trang An. After all, it is a world UNESCO site as well.
It's a relaxing trip that takes around 2 hours, with up to 4 possible routes, both visiting caves and temples. There will be times when you get out of the boat, visit a small shrine and you can buy beers and snacks from local vendors. There's also a toilet at these stops. Nature around is incredible with many green lush bushes or little shrines erecting straight from the water.
Remember to protect yourself against the sun, especially if you decide on the tour around noon. The boat for two costs 800k VND.