Volume 1 of the 1992 book "The Gaver Families: A Jigsaw Puzzle History" indicates that the father of the Elizebeth and Rebecca Gaver who married Peter Miller:
After acquiring a copy of the 1992 Gaver book in the 1990s, I corresponded with the author. She was not aware of the Miller Genealogy book "Genealogy of the Relatives of William J. Miller" that was printed in Meyersdale in 1963.
Emmert F. Bittinger’s 1990 book "Allegheny passage: churches and families, West Marva District Church of the Brethren, 1752-1990" indicates that the original portion of the large Arnold stone house that is located west of Burkittsville is reputed to have been built by Peter Gaver, a Dunker who purchased the property in 1771.
The following image is from the "Petersville, District 12" map in the 1873 "Atlas of Frederick County Maryland". It shows where the above-referenced Arnold farm is located. It is the site of the now-lost Gaver Cemetery. According to the South Mountain Heritage Society, the western part of Burkittsville is located on the "Gaver's Recovery" tract.
The following excerpt from a 1910 topograpic map shows where Burkittsville and the village of Broad Run are located relative to the Blue Ridge. The current location of the Pleasant View Church of the Brethren is circled in red.
The following composite image is from Volume 1 of the "History of Frederick County, Maryland...". It shows that Peter Gaver and Peter Miller appear in the 1790 census records of Frederick County, Maryland.