Three men and a 7702-metre climb through the region's picturesque mountains

Greg Kew, Paul Watkins and Kerry Clapham are gearing up for the newest world class trail from November 23 to 26.

The course runs from Mt Zero in the north to Dunkeld in the south, climbing thousands of metres up a combination of sandstone slabs, stairs and technical rocky outcrops.

For Kew, training for the 100 miler (160kms) has been based in the Grampians and at Tower Hill.

He did Dunkeld's Peaks and Trails event in July and a "16 yards last one standing" in Adelaide in August to qualify for this weekend's event.

He covered 112kms in Adelaide and said the two events were brutal but cool.

Kew has been running "for a lifetime", competing in his first Surf 'T' Surf in Warrnambool when he was 20 and going on to race in dozens of marathons and ultra-marathons in Australia, Wales, France, Switzerland and China.

He said running solved all the problems of the world and was great for his mental health, providing him a social outlet but also solitude when he needed it.

Kew said he was equal parts eager and nervous but above all he was excited to be running with "a couple of locals".

Watkins, a high altitude mountaineer and ultra runner, is no stranger to pushing his body to its limits.

He has climbed major peaks on all seven continents and competed in some of Australia and the world's toughest ultra-marathons.

Ahead of the Grampians event he clocked up 100kms in the You Yangs, in southern Victoria, and 500kms through Sweden blizzards in March.

He joined Kew in the 50km Peaks and Trails event in July.

Watkins said ultra events were a form of therapy that cleared his mental inbox.

"You get to remind yourself that you can do hard things when you have to," he said.

The weekend's 100 miler will be different for Watkins who usually competes without a support crew.

This time he'll be joined by two friends and said it would be "just three dads" who don't always catch up due to life's busy schedule.

"I'm just going to run and enjoy it, have a beer at the end and celebrate having a weekend together as mates," Watkins said.

"I'm super pumped to get going."

Clapham, the oldest of the three at 69, said he started running in 2009 - the same year Kew competed in his first Surf 'T' Surf.

Since then Clapham has ticked off 22 marathons and 40 ultra-marathons, travelling to Western Australia and Queensland and as far as New Zealand and South Africa.

He said he heard a rumour about the inaugural Grampians trail 12 months ago and had been following the event closely.

"I signed up the night it opened," he said.

"Since then people say 'why are we doing this?' but as Greg and Paul said, it's a mental clean out. It really is cathartic."

Clapham said he didn't think he would make the gruelling 100-mile distance during the Tarawera Ultramarathon in New Zealand in 2020.

"I said it was impossible and my pacer said 'is it impossible or is it just hard with pain?' and it is hard with pain," he said.

"I made it and that is what I am taking in with me (this weekend)."

Clapham said when he took up running 14 years ago he was healthy but decided to get fit.

"I started doing boot camps. I did 3kms then 5km, then 21, 30 and then 42, then 50, 80, 100 and then up to milers," he said.

"Once you're hooked that's it. It's just another dose and you go on.

"I'll get this out of the way and that's a miler at the start of the year and a miler at the finish of the year. Then I'll look for next year for a bigger one."