65- 1992, LAX-XXX-YYY-ZZZ-DEN ...not UA, not a 72S, one of the stops is SLC but SFO is not on the routing ... the old Hughes AirWest map comes to mind, namely LAX-San Diego/SAN-Las Vegas/LAS-SLC-DEN ... which might actually have been Delta operating an ex-Western 737-200
86- 1992, TUS-PHX-XXX-MIA, not USAir, and a jet manufactured in Long Beach ... I'm going with what I think is the lower-probability guess first: a Northwest DC-9-50, with the second stop in Memphis/MEM