Steinbeck really is master of painting a setting. The setting is quiet, even pristine, with trees, leaves, and a gentle breeze. There are also animals, rabbits and a heron. The only evidence of humans is a footpath made by boys who probably use the pool of water for play. This idyllic setting gives the impression that we are in a utopian society. Even how the section ends is beautiful.
The sycamore leaves whispered in a little night breeze.
However, as we read the section very closely, there are a few details that show that the setting is not a perfect place. First, when Lennie drinks deeply from the pool of water, George warns and chides him, because the the water might not be clean. The day before Lennie got sick. In addition to this point, Lennie is holding a dead mouse. Lennie actually killed it, because he does not know his own strength.
In view of these last two points, the setting might be beautiful, but there are also signs of suffering and death. These foreshadow that all might not be well.