You mention muju, so on the point you made above about lunacy at korean ski resorts:
The bottom half of muju in all zones is a mess. Possibly the side with the dominoes pizza place is a bit less well travelled, but it also has incredibly slow lifts.
Stay the hell away from the bottom half of the hill. Also avoid the green runs (blue runs in US iirc). Theres nothing more hilarious than 3pm at the bottom half of the mountain trying to ride through about 2000 people completely out of control with ski patrol blasting their whistles in the hope that order was somehow magically materialise.
Up the top though on the interemediate lines, nary a soul to be found. So long as you can charge a steep of about 35 degrees, go grab yourself an ego boost with hundreds of people AMAZED that you even tried to ride it let alone pointed the board straight down and wrecked it. Its fun

Plus, no lift queues on the half way hill back up to the top... well, not many. There are a few people who run the green path coming round skiers right - its their only realistic option if they arent up for a side sliding down a steep).
First time i went there i spent my morning on the left hand side (skiers left) of the mountain (i figured id hang about there in the morning so i could grab pizza for lunch)and almost tore my hair out at the queue at the bottom when i finally decided to head for the top. I almost went home in a sulk. But i promise you, get past that mid point and its a different mountain. Sure, realistically it means youre riding half the mountain (dont cross the middle). But its pretty decent terrain up there if albeit a little short.
Also, dont try and ninja into the trees. Its total ice. Even withrazor sharp mtx youd struggle to grip on.

Lessons from the past