Tracey Howe, 61, has been walking for more than two months in memory of her wife, Angela White, who died of cancer.
She set off from Glasgow on November 1 and plans to complete a year-long circuit of the British mainland coastline.
So far, she has walked 900 miles through North Ayrshire, South Ayrshire, Dumfries and Galloway in Scotland, and Cumbria in England.
She will be walking from Nash to Mathern on Friday, February 7.
The retired professor has raised more than £20,000 of her £100,000 target for five charities.
Ms Howe said: “Angela left a horrific gaping hole in my life when she passed away last September aged just 58 but I want to turn my grief into a positive.
“The long walk, which I have called Tracey’s Trek, will be the hardest thing I’ve ever done.
“It will be tough mentally and physically but I think Angela would be proud of me.”
The charities benefiting from her trek are Beatson Cancer Charity, Marie Curie, brainstrust, Breast Cancer Now, and CoppaFeel.
She said: “The NHS, The Beatson, and Marie Curie gave our family tremendous support when Angela was diagnosed with cancer.
“She had two blood cancers, myeloma and amyloidosis, which her doctors described as the most aggressive they had ever seen.
“I am also supporting brainstrust because prior to the cancer, Angela had also suffered a brain tumour.”
Ms Howe is walking an average of 20 miles daily, six days a week, to complete the anti-clockwise circuit of the entire mainland British coast.
Friends, family, and her dog, Poppy, are accompanying her in a motorhome.
She is appealing for people along the route to offer a place to park and join her for some of the miles.
