"Such was the case when I heard Glenn Miller and Lena Horne on the radio today." (page 87)
At the USO dancfe, two songs played a significant role during Liz and Morgan's encounter:
The first was "Stormy Weather," a tune reminiscent of both of their mothers. Lena Horne recorded it several times throughout her career, most notably for the 1943 film Stormy Weather.
The second noteworthy song during the scene was "At Last," to which the couple shared their interrupted yet magical slow dance. The ballad was originally recorded and popularized by Glenn Miller and his orchestra.
"Your words painted such a vivid picture of evenings spent amidst the quiet cornfields and blazing sunsets." (page 143)
In a letter, Morgan mentioned sitting on a tractor in the fields while admiring the sunset. However, only in person did he explain to Liz that he used to specifically harvest corn.
"I had not thought of those verses in years. It seems a lifetime since I studied literature of the like with my father." (page 144)
These lines along with the Byron poem are indeed telling hints, as during their conversation at the USO, Liz told Morgan she planned to be a literature professor, thereby following in her father's footsteps.
"I smile now recalling occasions on which I, too, had made my father proud—the day I received a gaudy blue ribbon for my first short story contest; and, of course, the evening I debuted in a school play as a singing pine tree. (An off-key one, at that." (page 144)
Here she mentions her penchant and aptitude for writing, again linking her expressed career path. She also admits to having been an unskilled singer—in contrast to Betty, who we know has a decent singing ability, based on her USO job as well as Liz's thoughts.
"Aside from wishing those clouds away for you, I can offer only a relevant poem, as Swinburne's eloquence so greatly surpasses my own." (page 225)
Liz's knowledge of classical literature is confirmed once more with her citation. The brief analysis that follows in the letter further relates back to her mention of plans to become an English professor.
"Though a newborn never did arrive down our chimney, years later I met my dearest friend, Julia." (page 227)
During the start of their meeting, Liz had introduced Julia to Charlie right in front of Morgan. However, by the time he reads this letter, we can safely assume he has forgotten Julia's name.
"Though I had the pleasure of meeting Charlie only briefly, the goodness of his character shone brightly through. His ability to make people smile, as well as his infectious zest for life, I will forever hold in my memory." (page 226)
Here, Liz makes it clear she had spent enough time with Charlie to make such conclusions about his personality. He had certainly displayed both traits in Liz's presence at the dance.
"The scarf, knitted by a cherished elderly friend, I pass along to you now..." (page 268)
Although she didn't provide specifics, during their chat Liz did tell Morgan that her work involved caring for elderly folks, describing it as: "a job I love for some reason." Of course, as you know, Viola is among those folks and most definitely a "cherished elderly friend."