Looks like this is back. BWI-IAH-SFO-TUS-SFO-IAH-BWI for 3.4CPM. In ITA, most dates in September and October available for $245.80.
Baltimore (BWI) to Tucson (TUS) - Sat, Sep 1
Baltimore (BWI) to Houston (IAH) - Sat, Sep 1
United 1491 Dep: 8:25AM Arr: 10:27AM 3h 2m Boeing 737 Economy (G)
Layover in IAH 3h 58m
Houston (IAH) to San Francisco (SFO) - Sat, Sep 1
United 1045 Dep: 2:25PM Arr: 4:51PM 4h 26m Boeing 737 Economy (G)
Layover in SFO 2h 39m
San Francisco (SFO) to Tucson (TUS) - Sat, Sep 1
United 6352 Dep: 7:30PM Arr: 9:30PM 2h 0m Canadair Reg. Jet Economy (G)
OPERATED BY SKYWEST DBA UNITED EXPRESS
Tucson (TUS) to Baltimore (BWI) - Sun, Sep 2
Tucson (TUS) to San Francisco (SFO) - Sun, Sep 2
United 6369 Dep: 6:40AM Arr: 9:00AM 2h 20m Canadair Reg. Jet Economy (G)
OPERATED BY SKYWEST DBA UNITED EXPRESS Layover in SFO 1h 45m
San Francisco (SFO) to Houston (IAH) - Sun, Sep 2
United 230 Dep: 10:45AM Arr: 4:40PM 3h 55m Boeing 757 Economy (G)
Layover in IAH 2h 50m
Houston (IAH) to Baltimore (BWI) - Sun, Sep 2
United 1268 Dep: 7:30PM Arr: 11:42PM 3h 12m Boeing 737 Economy (G)
Cost per passenger (including taxes & fees) $245.80
Total cost for 1 passenger $245.80