My sister-in-law and her husband are flying from LAX to BKK to visit us. They've managed to get a trip with frequent flyer miles but it involves a 12hr stopover in Seoul each way.

They are not frequent travellers and they don't have a big budget so what would you recommend them to do in 12hrs? Fortunately, they are daytime hours that they are there.

I've only been to Seoul a few times, always on business, never longer than 36 hrs. I know that they can take the Limousine bus from the airport to downtown but are there better alternatives? What should they see, do, etc.?

Thanks for any suggestions to make their trip more interesting! ^