I propose 2025-12-13 to 2026-01-26 (45 nights). Please confirm these exact start/end dates and whether you mean the crossover into 2026; seasonal differences matter for islands and highlands.
Do you want a relaxed trip (longer stays, fewer moves), active/adventure (treks, scooters, day hikes), cultural/food-focused, or a mixed balance? Also confirm interest in cruises (Halong), domestic flights, or trains.
Do you want a full day-by-day plan for all 45 days (very detailed) or a high-level 2–3 week core itinerary with add-on options to fill remaining days? Full detail means many restaurant & time recommendations.
List any absolute must-see places (e.g., Sapa, Hoi An lanterns, Phu Quoc beaches) and dietary restrictions (vegetarian, allergies) so I can tailor meal recommendations.