Unfortunately I am not the best person to answer your questions, but I'll try. Hopefully someone with more info can contribute.
First of all, about the cat in the bus question, I'm sorry to say I don't know, I've only taken cats in taxis and trains, without any problem. There's a thread about cats in buses here: http://www.animalrescuekorea.org/for...ead.php?t=5062
Also, I cannot help you with the travelling instructions, I don't even know where Seosan is...
If somebody can answer this question, please do.
Sorry for not being able to help.