Some info for those not familiar with traffic in Korea;

The "Highway Bus" or "Ko Sok" bus is probably the best way to travel on any highway in Korea, particularly on holidays & weekends. One reason is that the toll highways have a "Bus Lane" which is designated exclusively for buses and vans with 8 passengers at certain times and days. When congestion occurs with other cars and trucks, the buses are flying by as we sit and poke along in our privately owned vehicles. Even on a regular day they seem to run at the speed limit or higher, and rule the highways.
Weekends and holidays are a real pain for driving your personal vehicle on the big highways. It seems like every Korean family has two cars and go out on the weekends and holidays. A stick shift is a REAL pain in slow stop and go traffic. Don't bring a stick shift vehicle to Korea unless you only drive from home to the PX and Commissary.
Our gas is $3.35 and more, and the Koreans pay more. The buses and taxis are cheaper, and you save on upkeep and insurance. the side roads are narrow and cars park everywhere, often sticking out into the street. I do not recommend a full size car or SUV. You will get it scratched up and scraped driving ,or even when parked sooner or later.