Click here if you would like to read an overview of my 3 months experience in Vietnam.
If you like to have the "turn back time" kind of experience, then you should go to Hue, Vietnam's Ancient Capital filled with majestic palace and tombs, and also plenty of local cuisine to try. To me, two days in Hue is more than sufficient. I spent about 4 days there hanging out with my local friends :)
I booked a bus to Hue from my hostel at Phong Nha and it cost $10. It's only about 3 hours.
I stayed at Freedom Hostel, which i highly recommend. Find out more about it from my best hostels experience write up at the bottom of my overall Vietnam trip page.
Places and things that I would recommend you to go and try are:
Overall, I had such an enjoyable time in Hue thanks to my local friends and the very warm and friendly hostel owners. I don't think I will enjoy it as much if not for them. Very grateful.