When I got my 72 VASS'ed about 6 years it was recommended I contact Kevin Williams from Plenty.
The VASS cost me $800 back then from memory, so I'm assuming it's probably a little it more than that by now.
It was a couple of hours work to do all the checks on his list, however a majority of that was a formality as our ADR's were mostly copies of the US design rules, but the VASS engineers still need to check it all out to be sure it conforms. Rust in the car is a big no-no.
After the main inspection I was instructed to:
Australian Standards seat belts to be installed, lap/sash front and rear
Headlights changed for ones that dip to the left
Fix a loose seat back
Put some heat proof tape on fuel lines that ran within a couple of inches of the exhaust
Leaving the taillight/blinkers red was ok.
The second (final) VASS inspection was to just check that I'd fixed these things and then he filled out some forms and handed me the cert.
Back then the VASS cert only stayed valid for a month after sign off (assuming it's still the same now?), so you had to coordinate your road worthy cert and VicRoads appointment to coincide with the VASS time period; if you miss the window then you gotta pay for the VASS again! Best idea is to book for a preliminary RWC first so you can fix up anything obvious that they pick - fer instance there'd be nothing worse than getting your VASS cert and while the clock it ticking down on it's validity you find your roadworthy guy doesn't want to pass your red blinkers for example.....
Obviously if you can find a VASS engineer that does RWC's then that will be an advantage to avoid the coordination effort listed above.
Here's a link to the list of Victorian approved VASS engineers (Word document download):
http://tinyurl.com/ofzhdwf