So a girl in her late 20s has already demonstrated the will to complete college, seminary and ordination. She is used to tackling big challenges and seeing them through to completion. I believe she can do it and as her uncle, I hope you will catch some of her determination and
believe she can do this.
She isn't planning on thru-hiking 2016, she has said that in a few years, she wants to take a sabbatical and do this. She already has the soft skills and determination to get this done. If you want to help her, don't try to make it hard on her, start introducing her to the technical details of sleep, shelter and cooking.
Be the good uncle. Don't rock the apple cart, show her the apple cart that people who love the outdoors use.