Upvote:1
In his book, "Confessions of a Buddhist Atheist", Stephen Batchelor, Spiegel & Grau, Random House, 2010, describes his experience of doing just this in 1981. Batchelor's first Zen retreat was at Songgwangsa, under the guidance of Kusan Sunim, and he stayed until 1984, a year after Kusan Sunim's death.
Upvote:1
There's The Hwa Gye Sa International Zen Center. I know nothing of it but its web site (i.e. that it's "international", Zen, next to Seoul, and has retreats with an application form and an email address); and that in 2007 Hyon Gak Sunim was teaching there.
It also a page with three or four links to other places (one of which is Mu Sang Sa).