Fiona Foster (nee Cupitt) graduated from Chevalier in 1994 and Rachel McRae graduated in 2009, but they will share a unique experience.

While it will be Ms McRae's first experience, it will be Mrs Foster's fourth trek.

"RSL NSW sponsor kids between 17 and 22 years old to do Kokoda and Castle Hill RSL sponsored Rachel," Mrs Foster said.

"I'm going away as a leader, facilitating and mentoring kids on their journey."

Mrs Foster first hiked the Kokoda Trail in 2009 with her husband because her grandfather had fought on the track in WWII with the Third Militia Battalion, which was full of Mittagong and Bowral boys.

"There's a lot of mental toughness in preparing for the hike and when you're there you've got to get up everyday and say 'I can do this'," Mrs Foster said.

"Going over, walking it and understanding what those blokes went through, it's the best history lesson anyone can have.

"I've seen kids change their perspective on life over the course of the hike."

Mrs Foster engages in regular training to prepare for the hikes from general fitness to push-ups and Ms McRae said she had undergone a similar routine in preparation.

"I have been training with my personal trainer, Kayla Booty at C2K Fitness Centre, which is owned by Castle Hill RSL," she said.

"Kayla prepared a fitness program for me to follow to prepare my legs for the vigorous 100km walk, strengthening my back to allow me to carry my 15kg pack and a lot of cardio."

Ms McRae, who has been a member of the Royal Australian Navy, said the trek had been on her bucket list since she was about12 years old.

"The trail plays a vital part in our military history, but sadly not many people know this part of our history, which is why Castle Hill RSL and other clubs are sponsoring youth like me to walk the Kokoda track," she said.

"It is part of a leadership program started by Clubs NSW that sends young members of the community over to Papua New Guinea to learn about Kokoda and to build confidence and come back to their local communities as leaders."

The two women will fly out for Papua New Guinea tomorrow and the trek will take 10 days.

To follow their progress, like Adventure Kokoda on Facebook for more details.