G'day Will,
Welcome to Melbourne.
The only way to get to RWY 34 from the terminal is via Melrose Drive then to Link Rd.
From Center road to Operations road is all Cargo Area/ Airside / Fenced Off!.
You could walk, but will take you from anywhere from 40min to 1 Hr at a guess.
Melbourne has some strange weather & by the time you may get there the wind may have changed as well as the RWY operations, so may be a waist of time! But you never know.
You could ask for taxi but dont count on it as they usually dont like to take you very far. I live 17km from the airport & I could not even get a taxi to take me that far once before.
Their is a public bus that runs up & down Melrose drive (
www.tullamarinebus.com.au), you may try & catch that to a stop after Link Road.
Hope this can help.
Rgds
Karl