Please excuse by sticking "h" on my keyboard and other typos because I rushed and didn't proofread. Hope you will share your findings with us. In 1850 Coeymans, Albany County, NY census is a John Vanerppol, 53, with a wife, Sopia, 50 and three children -- Catherine 24, Gertrude 19, and John (jr) 14. If this is the same Sophia who was the mother of Frederick and John, the mystery is why those 2 younger children are not with them; also Sophia is listed again in the 1850 census in Fulton Co., NY with son George; I found Frederick in the household of Jesse Brusher in Fulton County in 1850. While divorce was fairly rare in those days/place, it is not unheard of, so worth exploring. If Sophia's husband, John died about 1850 that might explain why she removed to Fulton County and why the two younger children as there. This is all conjecture.
Good luck with your search. -- Myra Vanderpool Gormley
P.S. There are several Van Buren connections (intermarriage) in the Vanderpool line --in differene lines and time periods.