What are the contrasts in the poem "Summer in the Yakima Valley" by Ruth Roach Pierson?

The speaker divides this poem into two sections, introducing them with the comments that she thinks differently of the house and the valley "by day" to the way she does "at night." This immediately indicates that the two sections will contrast each other, particularly because the delights she describes from the daytime then lead into the word "but." By day, she has loved the house and the valley, but at night, everything changes.
By day, the speaker is part of a pair, "my cousin and I." By night, however, she finds herself "alone," which draws a contrast between the camaraderie of the daytime and the loneliness and fear of night.
By day, the speaker moves around the valley with confidence ("swaggered") and the only things to fear in it are "cow pies." By day, the house on the hill is "loved," a pleasant place to spend a summer.
By night, on the other hand, the speaker, now alone and without the support of her cousin, finds the house to be full of "nightmare shadows." Likewise, the valley itself is "alien," full of unknown sounds such as the call of coyotes. The speaker finds herself desperate to return to her own home.