English Tourism for my visiting family: can we make it NOT a nightmare please?

The Reddit community hasn't failed me yet, so maybe you can help me out: I'm very, very new to South Korea (I've been here about a month) and my family is planning a trip to come visit me in a few months. They're looking for "important things to see IN ENGLISH on a brief, 10 day trip to Korea with limited funds." They know they want to go to the DMZ and the Suwon Fortress. They might take a Suwon Bus tour as well. Does anyone have any ideas for what they should do? I just don't know the area that well yet. They'll be staying in Yeongtong-dong, Suwon, so places close to that or in the Seoul general area would be great.

TL;DR: My family is visiting soonish and want ideas for things to do in the Suwon/Seoul general area. English speaking please :)

Thanks so much for your help!