I've been looking into this and I think, based on the description and potential connections to NAMUS 44, there's a possibility this could be referring to Anita Scott.
Anita Scott – The Charley Project
-She definitely appears to have "pale skin"
-She had not a wealthy grandmother, but a wealthy uncle, who left her millions of dollars when he died
-She drove a '86 Volkswagen, which is notably kind of odd for someone of her age and means (and we also know that Keyes specifically differentiated between newer and older style VW's from his description of the "newer" VW bug that his near-victim in Vermont drove)
And she could be linked to the NAMUS 44 as follows:
-Richard Petrone and Danielle Imbo disappeared on 2/19 or early 2/20 of 2005, from Philadelphia
-Anita disappeared on 2/20/
2003, from just outside Philadelphia, and her car was subsequently found in Philadelphia
-(slightly more tenuous) Tony Luzio from NAMUS 44 disappeared from Delaware County, Ohio; Anita disappeared from Delaware County,
Pennsylvania
I am up to date on TCBS now, but I didn't write down the timeline of when Keyes is/isn't accounted for outside of the FBI timeline, so I'm not sure if her disappearance clashes with those dates, but as far as I know it does not. I do know, though, that Josh strongly believes there is at least one unknown victim from PA, although his rationale for that was somewhat more vague than most of his strong beliefs related to Keyes.
Thoughts?