Hints:
1. What do the two strings have in common?
2. What does the title mean?
The title of the puzzle, "182.2 Smoots", means "Halfway to Hell": it's half the length of the Harvard Bridge. So all you have to do is line up the two strings and take the letter halfway in between each corresponding pair. So:
NCIL SACOEBBD FM TH RDC AEUEF DDQNCQL AM GANKDRED HQ RJ UFEG THIS SENTENCE IS TO THE GIVEN LETTERS AS HARRISON IS TO WHOM ZMIZ SIYYEZDF LY TV VLG MMWEV TFWZGSZ AY IAVYNTYX JU VT YJYS
All right, so the relationship of "this sentence" to the given letters is just that it is halfway between them. So who is Harrison halfway between? Grover Cleveland was president immediately before and after Benjamin Harrison, so the answer is CLEVELAND.
2006 MIT Mystery Hunt