Hmmmm, they aren’t on “The Stoned Guest,” the only PDQ Bach I own. But while researching I found this online program that sounds like the “gentle introduction” requested in the OP. I haven’t listened to it yet (the whole series sounds fascinating) so I’m pointing but not recommending.
I highly recommend the soundtrack to Naqoyqatsi. Of the three films in the Qatsi trilogy, it has the best soundtrack. Although, if you get the Powaqqatsi soundtrack, you can hear where John Williams got his ideas for the celebration music at the end of Phantom Menace.