How does George describe Lennie and his dream?

To answer this question, take a look at the conversation between George and Slim in Chapter Three. To Slim, George describes Lennie as being "dumb as hell" but notes that he "ain't crazy" nor is he a "cuckoo." He does, however, describe Lennie as being a "nuisance" because he can't rid of him.
Later in this chapter, George gives the men some details about his dream. Notice that George has a clear, vivid image of the place that he wants to build with Lennie:

"Well, it's ten acres," said George. "Got a little win'mill. Got a little shack on it, an' a chicken run. Got a kitchen, orchard, cherries, apples, peaches, 'cots, nuts, got a few berries. They's a place for alfalfa and plenty water to flood it. They's a pig pen-"

What we learn from these descriptions is that although George gets frustrated with Lennie's lack of intelligence and neediness, he clearly feels a sense of friendship, loyalty, and devotion to him. This is shown by his detailed dream of the ranch, a place that he intends to build with Lennie and that will cater to both of their needs for their rest of their lives.