We first hear about these fantastical "winter dreams" early in the story:
October filled him with hope which November raised to a sort of ecstatic triumph, and in this mood the fleeting brilliant impressions of the summer at Sherry Island were ready grist to his mill. He became a golf champion and defeated Mr. T. A. Hedrick in a marvellous match played a hundred times over the fairways of his imagination, a match each detail of which he changed about untiringly—sometimes he won with almost laughable ease, sometimes he came up magnificently from behind.
As the calendar inches closer to the depths of winter, Dexter is filled with an increasing ecstasy about the possibilities of associating with the very wealthy. During the harsh winter, he can't network with this elite group at the golf course where he works because it is frozen solid. Dexter is goal-oriented and on a mission to achieve the lifestyle which he accesses only via his job at the golf course when he's young.
But the material...
(The entire section contains 3 answers and 873 words.)