Never been on the AUS/NZ sub-Forum before.
But since there is a chance I might visit an old friend on assignment in Perth, could anyone answer the initial question ("road cycling for a 2-3 week trip") relative to the western side of your continent - in July/Aug. Tom has mentioned a wine region south of Perth? My style would be 100km/day - don't mind sleeping on the ground but prefer not to carry too much gear, so probably modest hotel/hostel.
Thanks.
edit: I should check for WA's rainy months.
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Vintage, modern, e-road. It is a big cycling universe.