I Am Looking for Information on Joseph Mason Who Died IN 1777

The information that I have is that Joseph is the father of Peter Mason who was a soldier in the American Revolution. Peter's application for a pension was approved, he entered the service at age 14, in 1778 (I believe his father died in 1777. I have found a reference to Joseph Mason on line (Ancestry) in HIstorical req. of Virginians in the Rev, soldiers, sailors and marines 1775-1783 by John H Gwathmey. the only information is the birth date 1740 (which would fit) birthplace, Virginia, Kentucky--which also fits--(I have found them in both states) Volume 111 Page number--390. How do I go about obtaining a copy of that page to see if there are any more "clues" or information? (I am rather new at this). I also have found a record of a will of a John Mason leaving property to his children, one was Joseph Mason) I believe that this is possibly my Joseph Mason and would like to obtain a copy--how do I go about that? Thanks, I hate to sound ignorant, but I am still trying to learn how to do this and finding records from a distance is a challenge to me. thanks Loneta Boyer