If I am going to play in really cold weather, I have a Thermasilk base layer set. I wear the bottoms, then a pair of cotton pants and if need be my rain pants over the top. I will wear the Thermasilk top, then a turtleneck (not mock) shirt so I can leave the neck unfolded to cover more of my neck, a long sleeve polo shirt over the top. If need be, I will wear a lined pull over windshirt or my rain jacket over the top to knock off the wind.
I have found with the Thermasilk stuff, you have to make sure the temps are not going to start out cold and warm up quickly. Your upper body may get a bit too hot if it does and you find yourself pealing off everything to get the Thermasilk top off.
One of the things that bothers me a lot is for my neck to be cold. So from my hunting days I have several neck gaiters and I will wear them playing golf on really cold days, even if I have a turtleneck on.