Quick dunes trip
Arrive and check in on the strip. Late afternoon: Fairy Stream (Suoi Tien) in Ham Tien - wade barefoot up a shallow stream past red and white sand cliffs, about 30 minutes each way, ankle-deep in the dry season. Then Red Sand Dunes for sunset, about 10 minutes by motorbike - arrive by 4:30pm. Seafood on the beach road for dinner.
White Sand DunesMũi Né Fishing Village
Sunrise jeep tour (pickup around 4:30am) or ride yourself - about 25-30km northeast of the strip, about 45min by motorbike. ATVs on the dunes are optional and pricey. On the way back, stop at Mui Ne fishing village while boats are still unloading - it's busiest 5-8am. Leave in the afternoon. This works, but it's rushed - 3D2N fits Mui Ne better.