Hello! That sounds like a wonderful tour across Jeju, Geoje, and Yeosu in South Korea. Here are some travel tips for your journey:

Best Time to Visit:
The best time to visit these South Korean cities is during the spring (April to June) and autumn (September to November) when the weather is comfortable, and the landscapes are beautiful. The summer can be a bit hot and humid, while winters can be quite cold.

Route and Accessibility:
Jeju, as an island, is accessible by air from most major cities in South Korea or by ferry from Busan or Incheon. Geoje and Yeosu can be reached by train or bus from most parts of the country. Public transport is usually efficient in these cities.

Accommodation and Booking:
The cities offer a range of accommodations catering to various budgets, from luxury resorts to budget guesthouses. Booking online in advance is recommended, especially during the peak seasons.

Clothing and Essentials:
Pack clothes suitable for the weather during your visit. For spring and autumn, layering is advisable. For beach-side cities like Geoje, don't forget your swimwear, sun-protective clothing, and sunblock. Carry essential toiletries as not all hotels provide them.

Health and Safety:
South Korea is generally a safe country with accessible healthcare services. It's still a good idea to have travel insurance. Also, keep emergency contact numbers handy, follow the COVID-19 guidelines, and stay updated with weather forecasts during your trip.

Local Etiquette and Respect:
Koreans value respect and courtesy. Learn a few basic phrases in Korean, bow slightly when greeting, and avoid loud behaviour, especially in public transportation. When visiting religious places, dress modestly.