Green’s Dictionary of Slang

go on circuit v.

(Aus.) of a prostitute, to tour diggings and camps selling her services.

[Aus]Bulletin (Sydney) 7 Sept. 14/2: Re the lydies who ‘travel’ their charms [...] almost the only ‘business’ done, outside the Westralian goldfields, is – barring Japs – by women who ‘go on circuit.’.