Try some of the earlier stuff with the original Mothers. too many to mention all the titles but well worth looking up. Takes some getting used to as all 'av ant gard' music does (it just grows on you the more you listen to it)
On another note one of my all time favorites is a jazz album called "The Grand Wazoo". If you liked Hot Rats it's right down your alley.
As a lifelong musician who plays several instruments I have a musical mind which I think is a prerequisite for appreciating music from Zappa and Beefheart.
Oh, I know -- I grew up with Freak Out!, any my high-school garage band covered songs from that album, We're Only In It For The Money, and Lumpy Gravy. I knew all the lyrics by heart, and played lead guitar -- not as good as Frank of course, but good enough for my suburban high school dances. We blew a lot of minds. :-)