Two days and one night is the minimum; three days and two nights is more relaxed (not counting the 5–6 hour drive from Hanoi).
- Day 1: arrive, walk around the Stone Church and Sa Pa Lake; afternoon in Cat Cat Village; evening night market and barbecue.
- Day 2: early cable car up Fansipan for the clouds; afternoon at O Quy Ho Pass for sunset (autumn and winter) or Ham Rong Mountain.
- Day 3: Trekking Lao Chai – Ta Van through Muong Hoa Valley (stay in a Ta Van homestay if you have an extra night), or visit Ta Phin for a Red Dao herbal bath; head back to Hanoi in the afternoon.
Tip: take a night bus or night train to save a day; avoid weekends and holidays, when it's crowded and rooms cost more.