Bus from Hue or Bus from Hoi An. When you go through the long tunnel just after Da Nang There is normally a pit stop for 30 min at Lang Co Beach resort. Before this there is the mouth to the estuary-i would recomend taking a walk to check out the sand bar here- if the swell is big this will be working.
Vietnam is cheap. and there are so many undiscovered places here.
Overview
Atmosphere
Watch out for holes while walking around in Vietnam. Mate of mine fell in one when walking home at night- a piece of rusty metal spiked his leg...you can imagine where it went from there.