On most Mekong River cruises, Tan Chau will be either the first or last stop in Vietnam as it is located close the Vietnam/Cambodia border. It's a bustling town with a variety of unique attractions within close proximity. Located in a region once known best for its silk production, most river cruise excursions will stop at a silk factory, as well as a rattan factory where straw mats, slippers and more are made. (A handful of tours will visit a shop where rattan weaving is still done by hand in the traditional way, rather than on mechanized machines.)
Like all Vietnam "ports" along the Mekong, your riverboat will anchor in the middle of the Mekong River and you'll take sampans to get from the boat to your destination(s). All tours will be provided by your river cruise line; there is no opportunity for independent exploration.