scale, in a landscape mind, can be define as the comparative perception of a body into space. Since this definition includes the word perception, it implies that the body will try to establish a relation between himself, the elements that compose a space and the overall scheme of that perceptible space
Normally, a grand scale golf course involves a large piece of property and open vistas that allows you to understand the size of the site. You can have a 300 acre golf course but if each hole is isolated by trees, forget the grand scale.
As said in the definiton, you have to feel small on the golf course or from another vintage point, you see a golfer, small in a huge valley for example.
But, just as important, to accomplish a large scale golf course, the course has to blend well with the site so that you feel the course is boundless.