In a large mixing bowl, beat eggs, oil and buttermilk.
Combine sugar, flour, baking soda, cinnamon and salt. Stir in vanilla, mix well. Stir in carrots, raisins, pineapple with juice, walnuts and coconut. Mix well.
Pour into a well-greased 9x13" baking pan. Bake at 350° for 45-50 minutes or until cake tests done. Cool.
For frosting, mix together all ingredients and beat until smooth. Frost cooled cake.