This definitely comes under the heading of "fast & easy" or Joyce wouldn't have it in her little green box. 
Beat together in a bowl: 3 eggs, 3/4 cup vegetable oil, 3/4 cup buttermilk (whole, low fat or skim), 2 cups sugar and 2 tsp. vanilla extract.
In another bowl stir together: 2 cups all purpose flour, 2 tsps. baking soda, 2 tsps. cinnamon & 1/2 tsp. salt
Dump the wet stuff into the dry stuff and mix it together. Then stir in 1 can crushed pineapple (8 oz.) well drained, 2 cups grated carrots, 1 cup coarsely chopped walnuts (optional) and 3/4 cup shredded coconut. In a lot of grocery stores now you can get a bag of carrots already shredded.
Pour into a greased/floured 9 X 13 pan and bake at 350 for about 55 minutes or until a toothpick inserted in the center comes out clean.
While cake is baking, make icing:
Cream together 1/4 lb. (1 stick) butter or margarine & 1 block (8 oz.) cream cheese - both at room temperature. Then add 1 tsp. vanilla extract, 2 cups powdered sugar, 1 tsp. orange juice and 1 tsp. grated orange peel. Stir well. If frosting is too stiff or too runny, just add a bit more orange juice or powdered sugar.
Frost when cake is completely cool.
Joyce