Re: John Anderson Simpson - Fristoe's vet pensions
Here's another thought -- the Grooms roster that Carl referred to consists of the few official Compiled Service Records of Fristoe's regiment (which do not include John A. Simpson), supplemented by information from a wide variety of non-official sources (which does include John Simpson). You might want to check out some of those sources, see where they came from, and maybe uncover another clue or two.