Hi Brian.... Didn't find a marriage for Isacc and Jane Vandervoort, but this may be her brother, from Marriage Records of MOnroe CO., MI, Volume I, 1817-1864:
VANDERVOORT John, 21 yrs, R: Ash Township WALTERS Mary, 17 yrs, R: Ash Twp. M'd: 02 May 1839 in Ash Twp. in the home of William Walters M'd: by Edward B. Emerson, Min. at Flat Rock Wit: Isaac Drew and Jane Drebach, R: Ash Twp. Record: Page 147, Entry 1
That's the only mention I could find of Isaac Drew, and nothing on Jane Vandervoort.