The event, held for the first time last year, will be staged between February 24 and March 2.
It will involve 125 athletes from 15 nations, including New Zealand, running a course of more than 320km over tough terrain, including sections of the Alps 2 Ocean cycle trail, in seven stages in as many days.
Stages 1 and 2 (55.6km), from Mt Cook to Lake Pukaki, will be run on day 1; stage 3 (50.6km), from Lake Pukaki to Lake Middleton, on day 2; stage 4 (89km), from Lake Middleton to Loch Laird, on days 3 and 4; stage 5 (44.8km), from Loch Laird to the Waitaki River in Kurow, on day 5; stage 6 (53km), from Kurow to Peaks Rd, on day 6; and stage 7 (29km), from Peaks Rd to Oamaru, on day 7.
Sandri said the course differed from last year's version.
"We've had a whole lot of other landowners come on board, which has allowed us to change the course a little bit and get off some dirty old gravel roads and sealed roads and get them back into farmers' paddocks and up into the hills more, so that's been really good.''
About 40km of gravel and tarmac road had been removed from the course, and 1500m of hill climbs added.
He warned competitors to underestimate the difficulty of the course at their peril.
"I think it will be tougher. I don't want to have to tell them that, but it is going to be.
"You can go on a gravel road and you can run it for 20 or 30 kilometres and it becomes a bit of a march ... whereas if you are up and down, your mindset is always thinking about something else. We are never going to get it perfect, because that's the challenge of the race.''
Money raised from this year's race would be placed in a trust and distributed to individuals, grounds and organisations when the need arose, and also used for maintenance of the cycle trail.
He was confident the race would be well-received by the runners, the more than 120 people who had made it happen and the wider community.
"If we put in the same effort and time into it as we did last year, it will be a success.''
