Changes

Getting out of Perth, take the train to Midland station, at the end of the line. From here take bus 320 and ask the driver to put you down on Great Eastern Hwy Before Park Rd A. There is a small paved rest stop area before the bus stop, where cars and even trucks can pull over easily, and good visibility of the road for some distance. Here you're out of the city already and should easily get a lift at least a few km along the road to the towns of Sawyer's Valley and Baker's Hill, which are good places to catch a longer ride as the road slows there for the townships. Further along is Northam, which the main highway bypasses (don't take a lift into the town, but rather stay on the bypass which is the highway). There is an ok spot to stand at the second turnoff to Northam, but it is just by the highway and people tend to be driving by fast. A lot of the traffic to (Kal)goorlie is worker dudes returning to work after a splash in the big smoke, easy rides, most traffic going long distance will be <12am.

The bus only goes once an hour from Midland, mostly at the half-hour but you may want to check in advance to avoid a long wait. You'll be getting off in Zone 3, so plan your bus/train ticket accordingly. Midland train station is also a famously bad area of Perth, so take care of your stuff and yourself, and don't be there at night if you can help it. But you'll be fine in the daytime and there are usually police around somewhere. Just be aware also that if you look too scruffy, drivers may hesitiate to pick you up on account of this.