booking-timeline When to lock what. Reservations have hard deadlines: lodgings fill, scenic-train window seats sell out, fees lock. Get the order wrong and the trip falls apart. The 4-tier cascade Render this as a Markdown table in the trip body. Adjust the lead-times by trip type (international ≥ 4 months out; domestic ≥ 6 weeks; weekend ≥ 1 week). What goes in each tier 4–6 months out (the lock-in window) Things that fill up earliest: - Flights — international flights are cheapest 4–6 months out; US domestic 2–3 months - Peak-season lodging — Swiss alpine villages (May–June), US national pa…