Even though Trapper John never got an official "goodbye" episode, this one can considered to be his unofficial sendoff, owing to the heartfelt speech Hawkeye gives his friend as he's preparing for his departure.
The blue Hawaiian shirt Radar wears the night of Trapper's party is the same shirt he wore on his date with Lt. Simmons in Springtime (1974).
When Hawkeye and Trapper are in Henry's office, and Henry gets the bottles of liquor to celebrate Trapper potentially going home to the states, because of his ulcer, Trapper declines any liquor because of his ulcer. And Henry says Good boy and tells Radar to get some milk for Trapper. The wives tale has always been that milk is good for an ulcer. However, milk may temporarily soothe ulcer pain because it coats the stomach lining. But milk also causes your stomach to produce more acid and digestive juices, which can make ulcers worse.