We have signed up for this tour and there are 5 more available. They had good reviews. There are two groups from Volendam already booked with them and we are the third group. Please read the following and email firstname.lastname@example.org directly if you are interested.
Port of Call: Nha Trang Nha Trang Special Countryside + City Tour by bus + River Cruise
$60 USD/person for a group of 10 tourists