The individual pursuit world champion (26) rode part of the Otago Central Rail Trail with the Otago Rebels during a pre-season team-building exercise some years ago and is looking forward to riding the popular track again.
She will compete in the teams category with her partner and coach, Craig Palmer.
"I thought 150km was too far to ride on my own with [the New Zealand] track camp coming up. So I roped Craig into it, although he has given me the uphill leg," she said.
While they are competing just for fun, and to help raise money for Cycling Otago, the pair are hoping to dip under the time their old flatmate Shane Melrose set in 2006 of 5hr 16min.
"Every time you get on the bike you go kind of hard, for sure. But mainly it is just a bit of fun and a good opportunity to get out and do a local race," Shanks said.
The former netballer will begin her preparation for the world championships when she links up with the New Zealand track team in Invercargill on October 4 and will stay in camp until October 17.
The next major event on the calendar is the Oceania Games in Invercargill in mid-November.
The first world cup event gets under way in Melbourne a week later.
Ultimately, Shanks is building towards the defence of her world individual pursuit title in Copenhagen, Denmark in March.
Rail Trail race organiser John Wekking said the event had attracted 250 entries, with competitors coming from as far afield as Hong Kong and the Netherlands.
The race begins at the Clyde railhead and finishes at the Middlemarch railway station.
Last year's winner, Nicholas Smith, holds the course record of 5hr 14min.
(Additonal reporting by Glenda Bruce).
