ULP or OPAL availability on the Tanami Track

Hi, We are looking at travelling the Tanami Track in June from Alice to Halls Creek. We have a Landcruiser Troopy fitted out as a camper van. The trouble is that it's a petrol vehicle with an LPG second tank. We get up to 800kms range on this setup (90l ULP, 90l LPG). If we do it, we'll need to refuel along the way...

I'm guessing that LPG will be unavailable on the Tanami, but what about ULP/ OPAL?

Cheers
Rob