Dave and Joel discussing words. "Alter Kocker?" "Altakoka." "Means 'ancient venerated one'?" The Yiddish term 'alter kocker' means 'old shitter', the equivalent to old fart. The Jewish alter kocker was a standard character in Borscht Belt comedy acts, an old, loud, heavily accented, rude, grouchy, difficult person, usually male.
While Maurice is watching footage of his Mercury launch, the announcer mentions that he had trained for six years and would fly 15 orbits. That means his flight would have taken place some time in 1964, at least six months after Gordon Cooper's last historic Mercury flight (but presumable before the April first Gemini flight). It also means his flight would be 7 orbits fewer than Cooper's flight.
Towards the end of S5E2, , Maurice disrobes and dives into the forest pool at the bottom of a waterfall. The music playing is the "D.W. Suite", by Lindsey Buckingham. This music theme is also played at the end of S2E5, "Spring Break", as all the men in Cicely start out on the naked mens run.