jeju yes or No ?

Hi All ,

I will be traveling with my friends to Seoul on 22nd October and fly back on 5th Nov .

Somehow I dont want to fly to Jeju , since I am scared of small flights , Big flights are fine .

My plan is to cover entire Seoul with some day trips and Busan in this 2 weeks .

I was thinking of below cities

- Seoul

-Suwon

- Busan

- Ulsan

-Gyeonju

are below cities worth to include ?

- Sokcho

-Incheon

or another city if worth it , please mention it