Hi I posted this question a few days ago but got no reply. Today I found put myself so just thought I would share.
On Thien Thuat Road in Nha Trang a blue and white bus goes up and down about every 15 minutes to half hour. There are lots of bus stops that are yellow and white. (The bus won't stop there, even if u wave). Walk to the end of the road where the road meets with Le Thanh Ton. about 10m before the end of the road there is a blue and white bus stop on the left side of the road (just in front of a shop selling Mobile phones). There isn't one on the right side of the road but if you stand opposite the one on the left it will stop. Get on and tell them "Ba Ho". It cost 18000 dong per person and takes about 45minutes. At the stop there is a big sign post for BaHo.
Follow the dirt track down and somebody will offer you a motobike taxi if not its only 3km walk. We got a free taxi off a local on the way and walked back. Entrance was 15000 each, it wasn't too far and is a nice place to walk all the kids come over to us and try to speak English.
Hope this helps.