The Advertiser has more details about Trisha ... (paraphrased)
Trisha and her partner Tony moved to Andamooka 8 months ago - with 2 school age children. Trisha has 6 children.
Trisha and her friend, Ms Conniff, had gone to Roxby Downs hotel that night to pick up takeaway beer for Trisha's partner.
When they got to the pub, Trisha didn't have money for the beer - so an unnamed man paid for the beer.
When Trisha left Ms Conniff's family friend's place in Andamooka at about 2am, Ms Conniff says Trisha was clear headed and had very little alcohol in her system.
Tony went to Ms Conniff's place in the morning and said to her stepfather that Trisha and Ms Conniff hadn't come back. That was when Ms Conniff learned that Trisha hadn't made it home.
Trisha's car was apparently found with the passenger seatbelt clicked in, the headlights were on, the windows were down, the car was locked, no keys.