I was in Richmond this weekend at the state library & archives and discovered several publications on Prince William County records. You might consider contacting the compiler of these records. I estimate that there were at least twenty volumes. The compiler of the records was Ronald Ray Turner and his addresses are below. I Google him and found one email address for him. I don't know if it's current, but you might give it a try. He sells his books, so if you share with him what research you're doing, he might suggest specific volumes you might want to search or purchase.

Ronarld Ray Turner
9901 Greenview Lane
Manassas, VA 20109.
RonRturner@aol.com