Thank you, Sue. In fact I've looked at that 1860 family before. I had rejected it as our William H. for two reasons: His death certificate from 1935 gives his birth date as 12 Dec 1859, and his mother's name as Sarah (surname unknown), both of which differ from that which is in this Census entry.Maybe - this is actually him and his family, but his mother Sarah died between his birth and 1860, and Thomas remarried a fairly young woman Anna, shown as 27 in this Census. That would be more plausible if his birth date actually were 1854 rather than 1859.
But maybe with all these Gaskills running around Burlington County, there simply were two different William H. Gaskills, about 5 years apart in age, both with fathers named Thomas.Without further evidence, I have to learn toward this latter possibility, but I will continue to pursue this. It looks like the parents in the 1860 family disappeared between then and 1870 - as you saw, William and Hannah appear to have been taken in by some Lippincotts (and old family name in the Gaskill histories dating back to Salem, I believe!)
Obviously I need to look at this family more thoroughly over time, see if I can find any evidence with which to accept or reject that these two William H's are the same person.