Zara Dyer suffered life threatening injuries on September 3, 2016, following a horrific car crash in Grand Cayman where she was working as a scuba diving instructor.
She suffered a seizure at the wheel that led to her crashing into a wall and resulted in long-term brain damage.
The injuries - which included a broken neck, complete paralysis on her right hand side and six bleeds on the brain - were so severe that her family were warned that they should fly out to see her immediately.
But after spending more than a month in hospital abroad, and having undergone an intensive programme of treatment and rehabilitation ever since - which saw her learn to walk and talk all over again - Miss Dyer is now approaching the end of an amazing challenge.
Her remarkable recuperation led to her setting up the 3 Million Steps charity with her partner, Ian Brown, to support others recovering from brain injury.
And for the past five months, Miss Dyer and Mr Brown, have been trekking across the length of the country to raise funds for Suffolk-based brain injury specialists Livability Icanho and Lions Club International - after both helped Miss Dyer during the aftermath of her accident.
After setting out from John O'Groats on May 8, they are close to completing the 3 Million Steps challenge to Lands End, as they are due to finish the JOGLE route and arrive in the next couple of weeks.
With the aim of completing an average of 10 miles per day, Miss Dyer's father and charity trustee, Peter Dyer, said: "It has been more than five months of hard work.
"Zara has had some very tough days. She gets very tired and has been averaging about 10 miles a day, with plenty of rest in between.
"She has now completed well over 130 walking days with less than 20 to go."
The former Carlton Colville Primary, Gisleham Middle and Sir John Leman High School student has received "great support" along the way, with friends, family and Lions club members joining the walk.
Mr Dyer said: "Two of the physicians from Icanho joined in with the walk and people have been turning up along the route.
"When Zara said she wanted to do a walk, we thought it might be to Norwich and back - not across the length of the country.