Her remains were found surrounded by household items including toothpaste, handbags, a knife and fork and a vinyl record of The Last Waltz, recorded in French.

Believing she might have gone overseas to recover from the shock, Ms Mountford's family had not contacted police to report her missing.

A NSW coroner on Tuesday could not determine the cause or manner of her death, although police insist it was not by foul play or suicide.

Instead, it is believed Ms Mountford died in April 1971 from exposure, having eked out a simple existence for up to two years in the cave.

Her remains, discovered in 1981 by a 14-year-old bushwalker, were found near jewellery, newspapers and train tickets from April 1971 as well as a bank passbook.

She still wore her mother's wedding ring, and among her belongings was a half-written weather-stained letter that police attempted to transcribe.

"As work has been difficult to obtain since coming home in October 1968, I decided to revert to my old talent of art and modelling, thus I packed my haversack and came bush," the letter reads.

"So far have had a lovely time except for … being delayed by an undue … (possibly wog) [words in brackets added by police] which sapped my strength.

Have some lovely ideas re oils and pastels for the near future."

Her nephew, John Mountford, now aged 65, remembers his aunt had converted to Catholicism for a man she had met in Canada and was about to marry.

"The man she did this for ended up leaving her. I don't think she ever recovered from that," he told police.

"She was the type to think with her heart, not her brain."

Mr Mountford said his aunt had loved the outdoors, had an adventurous personality and had travelled to New Zealand, Canada and Africa.

She was "flighty" and would "breeze in and out" of their lives, so her choice to move to the cave was not surprising.

"I know that being left by a man would have affected her very badly. She was a dreamer and a bit unrealistic, so for her to go and live in a cave is something I would believe suited her personality."

Ms Mountford's younger sister Nola Stewart, now 84, was the last family member to have seen her alive.

Ms Mountford had left some clothes at her sister's home in Mortdale when she left in a taxi one day in 1969.

Mrs Stewart yesterday told the Herald it had been a shock when the family was told of her sister's fate, because they had searched for her for years.

A 1983 coronial inquest had been unable to identify the remains, but the case was reopened this year when the Missing Persons Unit conducted a review and was able to find family members.

Rather than providing comfort, news of the discovery of her sister's remains had been difficult for Mrs Stewart.

"Actually it saddens me more to find out what happened to her, because I thought that she was living somewhere and not bothering to get back in touch with me."

Mrs Stewart said she thought the Canadian man might have been a soldier her sister had met during World War II.

"I know that she did have an American lad [but] what one hurt her I don't know."