Barrett says she is not daunted by the massive challenge awaiting her in New York, despite the fact the longest race she has completed was a 27km trial run in Pyes Pa, Tauranga late last year.
"I am feeling confident about the marathon. Last week I had a really good week in training and I ran 100km in total, so that was really good. So I have no real worries about being able to finish the marathon but will probably be a bit nervous on the day."
Mother and daughter are both competing in the 19km-long course in the Karangahake Gorge on Saturday and Barrett is looking forward to taking on the trail run format.
"I have done a few trail run events before so I kind of know what I am up for, but I have never run this trail run before. It should be a good test of my fitness."
Saturday's event is the last for Barrett before she leaves for New York with Lyn and her support crew in the form of dad Trevor.
"It is exciting and as I have never been to New York before, it will be a big change."