Jeju for Chinese New Year (Seolnal) 2017: Any tips?

Hello, everyone.
My parents are coming to Korea in a few weeks and we will be going to Jeju for Seolnal (Chinese New Year).

I have only been to Jeju for a work trip that lasted less than 24 hours, so I was looking for some tips of where to go, what to see, and where to eat.

Thanks in advance!

PS. So far, I'm doing pretty well with updating a lot in 2017, but I have to dial it back a bit, I think. Going to run out of content soon, maybe.