. For the OP: have your kids said what exactly they want to visit in Korea Town?
... I haven't explored the area much but there is a mall that has interesting stores. http://www.koreatownplaza.com/plaza/index.php?paget=home
From Hollywood and Highland, you can take the Red Line towards Union Station, then switch to the Purple line (I think at the Vermont Station) to get to Koreatown.