Unquote #18 answer

The quote

I may not have gone where I intended to go, but I think I have ended up where I needed to be.

The puzzle as it was set

O NXR DWQ KXBC ZWDC UKCGC O ODQCDFCF QW ZW, EYQ O QKODS O KXBC CDFCF YH UKCGC O DCCFCF QW EC.

The key

Each code letter stood for one real letter (code letter, then the real letter it hid):

X → AE → BF → DC → EZ → GK → HO → IS → KN → MD → NW → OH → PG → RQ → TY → UB → VU → WR → Y

The most frequent code letter was C (15 times), which stood for E. Short words, apostrophes and repeated letters are the usual way in: a one-letter word is almost always A or I, and THE is the commonest three-letter word in English.