Thanks for your comments. From what I understand the apartment we are looking to rent is about 5 minutes walk from Gangnam station. As for what to do, I guess its the usual sightseeing, eating, and a bit of drinking. We're all in our 30s (no children coming). As for how long, only there for two nights. There is talk of going to the DMZ, but not sure if that will happen (some of us have already visited it before).