Kit, you may have this already but I found a marriage date for Henry Vansant and Mary A. Curry of November 22, 1858 in Cecil, MD.
After they lived in Radnor in 1860, they moved to Trenton, NJ in 1870.
Have you found out more about Henry and his father? Was his father Richard Vansant? I can't seem to tie Richard in with the other Vansants in Bensalem. My ancestor, Weaver Vansant was also from Bucks Co. born 1800-1810. I can't find his parents either. Perhaps Richard and Weaver were brothers?
If you'd like to compare notes and share information, please contact me.