Mr Gilbertson, who has been working as an outdoors educator for the past 20 years, said he had started out on his mountain trek in 2013 before his grand tramp earlier this year. He had put in 30 days of "big mission" tramping three years ago and after starting again this year had completed five legs of his journey from a point south of Hokitika through to Arthur's Pass; on to Lewis Pass and Boyle Village, where he had worked as a tutor at Boyle River Outdoor Education Centre after first starting as a tutor for Outward Bound; from Lewis Pass to Nelson Lakes; then after hitching to the West Coast and going bush at Kahurangi National Park through to Golden Bay.
He also, for the first time, traversed Hawke's Bay's Kaweka Range and beat a new personal path through the Ruahine Ranges, where he was tramping near the Sparrowhawk Bivy last week, the day before a NZ Army soldier was accidentally shot and killed by another hunter.
He hit a low point physically in the Ruahine Ranges and had decided to come out for several days before returning and completing that leg of his journey on Sunday.
Mr Gilbertson returned to the mission today and will spend 20 days in the Tararua Ranges, going in at south Ohau and traversing the main range, taking in the peaks and for a spell coming out at Holdsworth, near Masterton, before his final tramp that will bring him out at Putara, in rural Eketahuna.
He will take a food pack, four large maps, a compass, cellphone with GPS link and mapping program, a personal locator beacon, he said, and "my brain and my eyes which are a key to things like staying alive out there".
"It's more of a personal goal I got going that's an expedition-style journey. I've been dreaming about this for 15 years and need to do it before I turn 40."
He had also during two of the South Island legs spent time in the mountains with his former outdoor education teacher at Rathkeale College, Simon Gorman.
He said his classes with Mr Gorman had been pivotal to his choice of career and love of outdoor education.
"If I think about how different my life could have been and if I look at Simon, he's a mentor, a role model, an inspiration, and a bloody good mate," he said.
"For me this is a big challenge and a major thing but one of my greatest reasons for doing this is just to reaffirm how amazing our wilderness is and how important it is for our younger generations to share in those same opportunities."