My parents and I recently did a big road trip from Melbourne to Perth where we did around 8,846kms round trip where we left on 14th of September and got home on Sunday 15th of October 2023. The most accessible motel we stayed at was on the Nullarbor in Western Australia in a town called Eucla at the Eucla Motel. I stayed in room 29 and there was a ramp from the car park to the walkway and then they had a small wooden ramp going up into the room itself which had an accessible bathroom with a accessible shower and toilet which had a grab bar next to the toilet. If you are thinking about doing this road trip I highly recommend staying at this motel on your drive along the Nullarbor. They also operate in the Central Western Time Zone which is 45 minutes ahead of Perth local time.