Went with CIK group and had an awesome walk around!
However make sure to bring the right shoes (I didn't, as I heard it was an easy trek... i just wore my uggs to prevent the cold, and it was a really bad choice as we had to walk on rocks most of the times and I ruined them)
The festival was fun, all the activities I tried were for free (ice slide, ice sleigh, ice igloo, free warm warm ramen, etc.)
I don't know how to get there by public transportation but I'm assuming it's complicated, so I recommend going with a day trip group like CiK