Roseanne Fulton, who was born with fetal alcohol syndrome, will leave Kalgoorlie on a private charter flight returning to her home town of Alice Springs.
The breakthrough came as negotiations with the Northern Territory health department for 24 hour-community care arrangements are close to being finalised.
Ms Fulton, 24, is in custody because the West Australian court system declared her unfit to be tried on driving offences.
"Had she been fit to plea she would have served her sentence two or three times over by now," her adult guardian Ian McKinlay told AAP.
Ms Fulton is said to delighted about her impending freedom and is counting down the days on a special calendar.
"This will represent a turning point in one of the most horrific lives you could imagine in modern Australia," Mr McKinlay said.
He estimates there are about 30 other intellectually-disabled Aboriginal people in jails across the NT, Queensland and WA because of inadequate facilities to care for them.
Ms Fulton won't be subject to any legal orders.
However, Mr McKinlay wants a safety net put in place to counter the risk she could slip back into her old life of living in a river bed.
It's there she suffered abuse.
"They need to revert to a mandatory treatment order which gives the police power to rescue her from danger and take her to a secure care facility," Mr McKinlay said, adding Ms Fulton should be transitioned to community care.
Family support for her in Central Australia is "pretty thin" with only unwell elderly aunts and uncles.
Attempts will be made to reestablish contact with them.
In Alice Springs Ms Fulton will do some vocational training and sports activities like volleyball.
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