"Because I wasn't running I had the energy to work twice as hard and for twice as long in the bush, working trap lines, so I think I've built up a pretty good base fitness for this year," said Williamson.
He said his work is the perfect training for this race.
"You get really good at navigating through the bush quickly. You also get plenty of hills you have to climb every day. The down side is it's hard to fit in training runs after a long day at work carrying anywhere from a 5kg to 50kg pack. So I don't do much actual running, I've only done about six runs in the last month so I'm pretty slow on the road."
Williamson has a special affinity with this mountainous course. He is the Under 23 Goat Tongariro Record Holder and one of only a handful of men to break the magical two-hour mark.
That time (1hr 58min 22sec) came in 2011 when he was 17 and it was on his debut in The Goat.
It was the same year he won the Kawerau King of the Mountain for the first time.
"It's good to have a record but I should be able to do a better time this year if all goes well."
Williamson, a former NZ Junior Mountain Running representative, said The Goat is always an event he looks forward to on the running calendar.
"The track is pretty much the same natural surface as the rest of the mountain so it's a real off-road race. It's always a good race because there's always a strong field."
Speaking of a strong field, Williamson will face tough competition from one of the legends of the New Zealand multisport scene, Richard Ussher.
"It's an awesome opportunity to race a high-profile athlete like Richard Ussher. I just wish I had done more training," he said.
The five-time winner of the Coast to Coast is making his debut in the event that he has heard so much about.
"It has always been a race I've looked at and thought 'I need to do that one day,' and this year it fitted the schedule," said the 38-year-old from Nelson.
"I jumped at the chance to come and experience a run that always gets great reviews from its participants."
The Goat has a reputation for being one of the toughest trail runs in the country. It is a demanding adventure run from Whakapapa to Turoa Ski Fields on the Round the Mountain track, traversing the western slopes of Mt Ruapehu. The 20km course has over 1000m of vertical ascent.
"I have heard that you have to be goat-like to do well at it," said Ussher. "I am looking forward to meeting new people and catching up with some friends I haven't seen in a while. Also to running a track I have never done."
Ussher, who has taken on the role of event director of the Coast to Coast for 2015, is coming back to his best after a year of rehab on a badly injured ankle.
"I don't run as well on the really rough stuff as I used to but really looking forward to a challenging run and I'm sure it will be spectacular whether sun, rain or snow. The fitness isn't too bad, I've just been training without much thought of results which has been nice."
Tauranga runner Chris Morrissey will be looking for a result. The well-performed multisport competitor and adventure runner finished on the podium of The Goat in 2012. He was champion of the inaugural Tarawera Trail Marathon this month.
Meanwhile, Rotorua runner Colin Earwalker just keeps on running. The evergreen veteran will attempt his ninth consecutive Goat next weekend. He won the overall race as a 50-year-old in 2006 and has never been beaten in his age category, which is an impressive record.
Meanwhile, in the women's race there are two favourites for the title.
Richard's wife Elina Ussher will look to use her debut in the event as preparation for the Coast to Coast in February. She will face a tough battle from Ultra runner Shannon Leigh.
The Rotorua athlete was second in the inaugural Tarawera Trail 50km this month.
She placed in the Blenheim Marathon on Saturday and was second in the Rotorua Running Festival Half Marathon on Sunday.
Finnish-born Ussher said she has long held an interest in mountain running as it is huge in Europe.
"I would like to do more off-road running races but at the moment my main focus is still in multisport," she said.
"I have heard that it is a great event and that the race course is pretty tough and technical. I'm really looking forward to The Goat as a new experience and a great day out in the hills."
A total of 600 runners have signed up for the race, which has grown to cult-like status. It began in 2004 with 202 competitors and has grown incrementally each year.
They will be in for one of the toughest finishes of any run in New Zealand: a winding and heartbreaking ascent of more than 1km to Turoa, aptly dubbed Mama's Mile (as in, it's so bad you want to go home to your mama).
Williamson said: "If you haven't done The Goat before it's a good idea to be conservative in the first half because the second half is much harder. Save something for the end."
Another North Island Goat event, The Goat Goes Bush in the Kaimai Mamaku Forest Park, will take place on March 28 next year on a new 20km course from Wairere Falls to Aongatete Lodge.
The Goat alpine adventure run
When: Saturday December 6, 9.30am.
Where: From Whakapapa to Turoa ski fields on the Round the Mountain track, traversing the western slopes of Mt Ruapehu.
What: The 20km course has over 1000m of vertical ascent.
For more information visit: www.thegoat.co.nz