He only performed with Frank Zappa at the Palladium for four nights in a row in December 1976, but the results can be found on three Zappa albums.
May 2012, Randy invited a bunch of friends to perform a number of 'popular' tunes that he had recorded in his long career. In concert, at the Blue Note.
The concert included a Zappa piece (although I don't know which one).
"Randy Pop" has tunes from this concert. Unfortunately, it does not include any Zappa pieces.
Album cover and track list have been added to the United Mutations Archives.