You know, I never thought church work could be so much fun,"" says one of his aides to the Reverend ""Fay"" Hill and it's sure a switch from cake baking and crocheting, as is this tale told out of the Sunday school and parsonage of his North Avenue (New Rochelle, N.Y.) Presbyterian Church. More righteously than rightly, Reverend Hill decided that the ""real threat to today's law and order"" was ""Organized Crime,"" and he quickly recruited help from his parish to do some local penny ante crimebusting: numbers taken at the lunch-couette; butter from the Daitch's Shopwell; crap games in a local plumbing shop; and on. Before long the rookie versus the bookie is tailing many of them up and down the Thruway, sometimes in collaboration with Marv, an agent of the Internal Revenue Service. And would you believe it if you overheard the revved-up Rev on the hot line: ""Marvie, baby, Fay. Got a pencil?"" Even if you read it? Here?