A seven-day Seoul–Jeju trip costs part of a day each way for airport travel, the flight, baggage and a second hotel check-in. Keep Jeju only if the island gets enough time for a route or resort stay you both want.
What the transfer day can hold
Check out, travel to the airport, check in, fly, collect luggage and reach the island base before planning sightseeing. An early arrival may leave room for one nearby stop; a late flight may leave only dinner. Do not place a fixed reservation against an unconfirmed flight schedule.
Give the island a connected block
For a short stay, choose one Jeju base around the mornings and evenings you will actually have. A rental car may open routes beyond the bus network, but it also adds pickup, parking and return steps. Keep a shorter or indoor alternative for a wet or windy day rather than making every outdoor plan depend on clear weather.
Pay for a resort room only when you can use it
A pool or sea-view upgrade needs an unhurried arrival and some time before checkout. If you land late, drive across the island and leave early, the room may function mainly as a place to sleep. Put the resort night beside a light day, not the flight transfer.
What Seoul-only gives back
Staying in one city avoids another packing day and leaves more room for restaurants, shopping, a performance or a slower morning. If you want Jeju for a particular coast or resort, set those as the reason for the flight; if the island is only an extra destination, keep the week in Seoul.
Move heavier shopping toward the end of the trip, so it does not occupy the car or accompany you through several island stops. Before booking, compare the airports, flight times, baggage allowance, rental-car terms and hotel cancellation window for your actual dates.
Plan the Jeju days
Decide whether to rent a car in Jeju · Choose a Jeju base · Jeju rainy-day options · Check if a resort night fits