I just returned from a trip to Trenton, NJ where I visited the archives for a couple of days.
In so doing, I ran across a relevant Elizabeth Collins who died as a single woman in the early 1800's (I don't have it in front of me but I think she died in 1815?) in Deptford, Gloucester County, NJ. She mentions her brothers Isaac and Jonathan and sister Jane Collins and especially her niece Mary Strattan (my ancestor), among other relations. I know it's a stretch as there seem to be a lot of Collins floating around ... but does this ring a bell with your research?
Respectfully,
-ks