After he solved crimes in L.A. as Jim Rockford, he played the aging Earp doing the same in "Sunset"
[DOC] [TLE] Sunset (1988) - Trivia - IMDb [PAR] Although the film's plot is mostly fiction, it is true that Wyatt Earp and Tom Mix ... 
James Garner was actually a little young for the role; in 1988 he was only 60 
years old.