I see no real reason to not offer and market a suitable regional service through western Victoria. Rural population decline is a factor of many things but absence of transport is surely one; younger people can't find work and need to travel farther afield while the older ones may be past the age where they feel comfortable driving.
GSR have always run the Overland as what could be called a "sulky" service. It came with their deal to run the IP and Ghan with revenue support from the two state administration through which it passes. It has never within my experience been run with enthusiasm or any serious intent whatsoever to make money. Even the attitude of on-board staff has reflected this on occasions.
Without SG conversion via Ballarat either a change of train or use of gauge-convertible stock would be needed if the empty route across the plains was to be abandoned. There is no commercial reason to come this way - it's only because of the gauge.
So we are faced with an option of captive SG stock working west of Ararat on a fairly limited service which would replace some but not all of the existing road coach operations. It can also effectively replace the Overland which I'm sure GSR would happily drop if they could. Rolling stock has to be serviced somewhere which either means working into Melbourne or Adelaide though fuel can be supplied by road tanker at any suitable location.
Connections with the BG Melbourne trains at Ararat would be guaranteed and a single daily service perhaps on the lines of Horsham - Ararat - Horsham - Adelaide - Murray Bridge. One unit connects with a morning Melbourne trip, returns to Adelaide and finishes with a "commuter" run to Murray Bridge. A second unit does the reverse. A third unit would need to be spare as two cannot work two rosters 7 days a week - probably not even 5 or 6.
That creates a daytime journey opportunity into both capitals from the regions though not necessarily a there-and-back trip. It's maybe a bit far for that; I'm not sure how many people make trips like Horsham - Melbourne and back the same day.
It also preserves the Melbourne - Adelaide passenger rail link albeit with a change of train across the platform at Ararat and it creates a morning-in evening-out service for Murray Bridge - Adelaide.
If the Overland ceased any remaining state funding could assist in pump-priming the new operation. And with the marketing and branding of V/Line which isn't a squeaky-clean brand but arguably has a better reputation than the "Overdue".