Originally Posted by
invisible
There are two ways - one goes via mountains and takes about 5h and second - via tunnel. Unless specifically agreed in advance, tunnel route is default and you won't see much.
I still suggest to take train - quite a good experience, and even for four people it will cost less than hiring a car. Just make sure that you don't book 'private car' which is not much difference than VN Railways cars.
I had a private driver to Hue and after I mentioned how I wanted to take the train , he took a way that didnt include the tunnel and we went along the coast for much of the way and passed by where there was a US Observation post. Best of all it didnt take 5 hours more like 2 and I was able to view at several points the beautiful coast line, best of both worlds