Continue past the Red Dunes on the long, coastal road for a bulk of your journey; go straight through the small town and past newly-constructed RESORTS. When the stretch of coastal road ends, turn left and continue up the hill ignoring what looks like grassy sand dunes on your right.
Pass the only petrol station on the right, then take the first red-clay road on your right; a sign indicates that you are near the White Dunes. The dirt road is rocky and unfinished - everything a motorbike driver doesn't enjoy. Continue bouncing along for some time with the sprawling lake on your left side. Do not worry about the White Dunes appearing so far away on the left, the road eventually wraps around the lake and brings you to the parking area.
Parking for the White Dunes costs a flat 25 cents; always lock up your motorbike! A small footpath leaves the left side of the parking area taking you through a park with cafes, beautiful strands of pine trees, and eventually to where the sand starts.
If you wish to try your luck, grab a sled rental for under $1 before leaving the area; there are no options once in the dunes.
If you still wind up lost, try asking a local for Bau Trang which means "White Lake" in Vietnamese; good luck with the tones!