Signatures will strengthen government's mandate for a strong Zero Carbon Bill.
Climate Change Minister James Shaw hopes the bill will be passed this year, and is trying to get cross party support for it.
The trust has members in Kerikeri and Waiheke Island. Another tool it can offer is a carbon calculator, so that people can measure their own carbon emissions and the ways they can mitigate or offset them.
The calculator is online at www.carbonneutraltrust.org.nz.
Trust member Terry Goodall wants to raise awareness of climate crisis, and what people can do about it. Treasurer Inge Bremer said the trip shows holidays don't have to involve air tickets and carbon emissions.
Older people are the ones who have time to devote to the crisis, Treadwell said.
"We all feel strongly that it's our generation that dropped the ball on taking action on climate change."
They're calling their trip an eke (ride), rather than a hīkoi (walk) - a Waiheke to Pōneke eke. Much of the distance will be on cycle trails.
With them will be Kaitiaki, a stuffed toy representing the guardian of land, sea and sky.
The Whanganui meeting will consist of a PowerPoint presentation - if people want to be informed - and a discussion of what is being done here.
"It's also a fact-finding mission for us, about what's happening in other places," Treadwell said.