Just came back from a 10 week back packing trip in SEA. Backpacked Vietnam in 3 and a half weeks and I felt like it was still rushed. I started in Hanoi > Phong Nga > Hue > Hoi An > Nha Trang (full of Russians) > Dalat > Mui Ne > Ho Chi Minh. I took the sleeper bus to each city and it costed roughly 5usd to 15 usd. Vietnam is such a beautiful country and was probably my favourite out of the 6 countries I've been to. The highlight of Vietnam was renting a scooter in Hue and taking a 9 hour ride with stops through the Hai Van Pass to Hoi An.