take bus is straight arrive at the location and u only need to drag ur luggage to the guesthouse. take arex + subway. u need to alight at hongik, drag ur luggage to transfer to subway line 2. reach station u still need to drag ur luggage to your guesthouse.. u ownself do your calculation lo.. 
err.. in korea be prepared to walk alot. 10-15 mins walking distance is like nothing for koreans. if u can't walk that far, you might need to to double think whether you need to have free & easy trip or not. as alot of attractions in korea need to have alot of walking.. not to say some road is hilly as well 
if your aim is to shop for beauty products.. stay near myeongdong area.. namsan guesthouse 3 is the nearest.. or you can try out super junior new opening guesthouse at myeongdong if you are his fans..