A constraint-first approach to trip planning: lock the hard constraints, sequence the bookings, fill the days. Not "here are 25 things to do in X" — that's a guidebook. This is a planning rhythm.
When to use
- 3+ day trip, leisure or mixed
- Multi-leg / multi-city itinerary
- Trip with a fixed end date (event, friend's wedding, return-to-work)
Skip for: single-day outings, business travel where work meetings drive the timing, fully-flexible "I'll figure it out when I land" trips (they don't need a plan).
Workflow
Lock the constraints, in this order. Ask if any are missing:
- Dates: hard-locked or flexible by N days?
- People: how many, what ages, mobility constraints
- Budget: per-person all-in, or per-night-lodging-only?
- Style: hostel/AirBnB/hotel; backpack/checked-bag; pace (sprint/cruise)
- One must-do: ONE thing the trip is non-negotiably for. (Wedding, specific museum exhibit, friend's location.) The must-do anchors everything else; sequence the trip around it.
Book in this sequence (load-bearing).
- Flights FIRST. They're the least flexible and most price-volatile. Lodging adjusts to flights; activities adjust to both.
- Then the must-do (event tickets, restaurant reservations 30+ days out).
- Then lodging.
- Then high-demand activities (popular tours, museum timed entries).
- Then intra-trip transit (trains between cities) if it's a multi-city.
- Activities you can walk into get booked never.
Build the day shape, don't fill the day. Each day on the itinerary should be one "morning anchor" + one "afternoon anchor" + an open evening. Three back-to-back activities is a death march. Most trips overplan and the user comes home tired.
Travel-day math. A flight day is not a full day. Half-day in transit, half-day for "where the hell is the apartment, what's open, did the bag arrive." Don't book activities on travel days.
The buffer day. A trip of 5+ days needs one fully-open day in the middle. Use it for catching up on what you've under-experienced or sleeping in. Pre-planned trips fail at days 4-5 because there's no slack.
Output shape
**Trip**: <destination(s)>, <date range>, <N people>
**Hard constraints**
- <list of locked items>
**Booking sequence (with deadlines)**
1. Flights — book by <date> (typically 6-8 weeks out for international, 3-4 for domestic)
2. <must-do> — book by <date>
3. Lodging — book by <date>
4. <next priority>
**Day shape**
Day 1 (arrival): [morning: travel] [afternoon: <light anchor>] [evening: open]
Day 2: [morning: <anchor>] [afternoon: <anchor>] [evening: open]
Day 3: [morning: <anchor>] [afternoon: open / buffer] [evening: <anchor>]
...
Day N (return): [morning: <light>] [afternoon: travel]
**Reservations to make 30+ days out**
- <restaurant / event / timed entry>
**Notes**
- <visa / currency / vaccinations / weather window>
Definition of done
- Constraints listed explicitly
- Booking sequence has dates (not just "book flights first")
- Each day has at most 2 anchored activities + an open evening
- At least one buffer day for trips ≥5 days
- Travel days NOT booked with activities
- Reservations-needed-30+-days-out section if any
Gotchas
Don't optimize for "seeing everything." First trips to a city overpack. Better to leave wanting to come back than to limp home exhausted having seen the inside of 6 museums.
Restaurant reservations are the silent gotcha. Major-city tasting menus are booked 30-90 days out. If "dinner at the famous place" is on the list, book that BEFORE flights if necessary.
Jet lag is real and people deny it. International eastward flights: assume Day 1 is half-functional and Day 2 is fully functional. Westward is gentler. Don't schedule the must-do on Day 1.
Group dynamics break itineraries. Couples / families with different paces should plan SOLO time into the trip explicitly. "We'll figure it out" means one person dragging the other.
Weather windows. Some destinations have one-month windows (monsoons, hurricane season, fog season). Confirm the user has checked the weather window for THIS trip's dates, not "I went in summer 2 years ago and it was fine."
Cash + cards. Specific things that catch travelers: ATM withdrawal limits, foreign-transaction fees, cards declined by issuer's fraud rules. Recommend telling the bank, carrying small cash for first-day expenses.
The "one thing" can be wrong. Sometimes the user says "we're going for the food" but their plan has 14 museums and 2 dinners. Reflect this back. The plan should look like the priority.