Mix milk with sugar, salt, and butter, stirring until sugar dissolves, cool to lukewarm. Sprinkle yeast over warm water in a warm large bowl and stir to dissolve. Combine milk and yeast mixtures, add egg and half the flour, and beat until smooth. Stir in remaining flour (dough will be fairly soft). Turn dough onto a lightly floured board and knead 7 to 8 minutes until smooth and elastic, adding only enough extra flour to keep dough from sticking.Place dough in a greased bowl, turn to grease all sides, cover with a cloth, set in a warm, draft free place, and let rise about 1 hour until doubled in bulk. Punch dough down, turn onto a lightly floured board and roll into a rectangle about 22” x 10”.Mix pumpkin with sugar, spices, and salt and spread evenly over dough, not quite to edges.Sprinkle with 1/2 cup walnuts and the raisins. Roll up jelly roll fashion from the wide side, lift to a greased baking sheet, and coil into a ring. Cover and let rise again in a warm place about 1 hour until doubled in bulk.Meanwhile, preheat oven to 350 F. Brush ring with egg glaze and bake 30 to 35 minutes until well browned and hollow sounding when tapped.Mix frosting ingredients together until smooth and frost ring while still warm; sprinkle with remaining nuts.Serve warm or at room temperature.