Yeah, you have to work your way up to Red Zone Cuba.
I think it’s a little easier to pick the episodes to hold back until someone’s ‘got it’, rather than the ones to use as the introduction. You wouldn’t start with RZC or Castle of Fu Manchu or one of the KTMAs, and until they’ve got a handle on the characters, the departure and guest reappearance episodes (Mitchell, Samson vs the Vampire Women and Soultaker) lose a lot of their impact and meaning.
I would say go with an accessible movie that lets them concentrate on the riffing, so something like Santa Claus Conquers the Martians or Space Mutiny or even Bride of the Monster—which would lead you right in to Manos if they want to see the other half of Hired!.
Since this thread is back, I need to throw Prince of Space into the conversation. The wormhole host segments are absolute classics, and I get so much joy out of Krankor’s silliness.