I think it's interesting to compare this episode to other "high concept" episodes like "Charlie Wants an Abortion." Those episodes work because the structure defies our expectations of the high concept when the characters follow their own agendas.
The seriousness of abortion serves to underline the characters' depravity, and the comedy comes from the superficial and self-serving drives of the Sunny characters that drive the plot along lines that have nothing to do with abortion. Normal people's concerns only create opportunities for exploitation.
In this episode, the characters adhere to the high concept of the Ski Movie parody. They follow along with the structure and expectations of said genre. Although they make jokes or meta observations about the genre, structurally they don't depart from the expectations we have about the genre and how the story will develop within it.
Ultimately, I felt like there were a few laughs, but I found myself disappointed and underwhelmed by the end of the episode. It would have made more sense if the guest characters were trying to drive the Ski story forward and the Sunny regulars were derailing that storyline with their own BS.