Her design for the tiny house was a finalist in Auckland's Visionary Architecture Awards.
The building is to showcase New Zealand natural and reclaimed materials, and Whanganui art and craft. It will pay for itself by providing luxury Airbnb accommodation, and benefit the town by bringing in a new kind of tourist.
"I want it to be a wonderful little object, and something that people in Whanganui will really enjoy and be involved with," she said.
The relocatable house will rest on two long steel beams, and it may have a copper roof. Inside will be a private queen bedroom and single berth, as well as a relatively generous bathroom and open plan living and kitchen.
Beds will be "tucked under the curve of the hull" , windows face north and west, and a deck extend toward the river. The section will be landscaped with native plants, including a pohutukawa tree to give that "coastal bach" feel.
The interior will be luxurious, with leather wall panels and possum fur on the sofa. Whanganui glass and ceramic artworks will feature.
McDouall is looking for copper and brass items that can be reused, and craftsmen for interior work. She's open to all kinds of offers and ideas.
"It's going to be hard to build within any kind of reasonable budget, so I would appreciate all offers of help."
She can be contacted by emailing elinor@drawingroom.co.nz, and progress can be followed on her blog, http://drawingroom.co.nz/category/iona-project/.