Seems Challenging, yep a phrase i have heard many a time, or the other' too much going on".
I think Chris on the right track with songs rather than Albums, but as Zappa has a huge and varied back catalogue ( sure there is something for everyone) knowing what sort of music PaulD likes would be an advantage.
When i have introduced people to Zappa over the years i found very easy straight up, but still great songs do it. Then again most of the people i am talking about liked Zep, Sabbath, Floyd ,Cream etc used to a kind of beginning middle, chorus solo etc...
Tracks like 'Peaches' would be just too much going on .. Some never liked his guitar style, others heard some stuff and thought comedy LP'S with great backing band, you know the types, would do a kind of Zappa speak singing voice narration thing impersonation.

Back on topic-
Going by what Albums posted already, if paulD doesn't mind a bit of Reggae, then i would say try

LUCILLE HAS MESSED MY MIND UP- from Joe's Garage,

CREW SLUT the track before, then into LUCILLE. Even better.

Crew slut ,what a groove, and yes some typical Zappa stuff going on, but then followed by Lucille, shows how diverse he can be.
Then again if more into Jazz, then Grand Wazoo , Waka/Jawaka j etc ust for the horn section alone.
grrr cant figure out uploading you tube vids, keep getting your video will appear here, but nothing...