Traveling from West to East

Norseman
Fill up at the petrol station in town (BP ?) next to the Caravan Park (not on the main highway!).

Balladonia
Norseman to Eucla is 730km. If you can not make this distance on one tank of fuel : top up at Balladonia.
Also check out the museum here with wreckage of Skylab 2, which crashed nearby.

Eucla
Fill up your tank here. Fuel prices at all places both to the East and West of here are between 10 and 20 cents per litre dearer.
Good caravan park here, located right on the edge of the escarpment, with magnificent views over the land and ocean.
Good restaurant at the motel.

Penong
Eucla to Penong is 410km. Fill up in Penong. I found at the time fuel prices in Penong cheaper than in Ceduna.