Farewell
Carriage preparation
"Tie the strings" refers to securing baggage on a carriage—she's treating death as travel prep. The casual tone ("That will do!") makes dying sound like catching a stagecoach.
Downhill to judgment
The ride to Judgment Day is "partly down hill"—easier than expected. Dickinson undercuts Christian terror with practical travel logistics.
Held fast
"Everlasting race" could mean eternal competition or eternal journey. The ambiguity matters—is this about winning or just moving forever?
Kiss the hills
She asks someone else to kiss the hills goodbye for her—the only moment of actual grief in this brisk departure.