Wayne Hall is to set off from Loch Morar, near Mallaig in the Scottish Highlands, with only his German shepherd Jerry for company.
His journey will take in 25 lochs, and he expects to lose around 30lb by "living off the land", eating fish, berries and edible plants throughout.
Mr Hall is embarking on the trip to raise awareness and money for housing and homelessness charity Shelter Scotland.
The self-employed tiler, who is originally from Stoke-on-Trent and now lives on the edge of the Peak District in Staffordshire, had to leave his home of nine years when his landlord died and the property was sold.
Mr Hall and Jerry are expected to complete the expedition at Galloway Forest Park on his 47th birthday, on August 25. They will be braving the elements and camping wild throughout the trek.
"When I found out that I was to lose my home of nine years my initial reaction was sheer panic," he said.
"Then I realised that I'm quite lucky. I'm in a position to find a new home and settle down somewhere else. Others are not so lucky. I chose to raise funds for Shelter Scotland because I empathise with anyone who has lost the roof over their head or is at risk of homelessness.
"It's one of the most frightening things a person can go through. That's why it's so important that organisations like Shelter Scotland are on hand to help people in need.
"I'm excited to embark of this adventure, but I don't relish the thought of losing most of my creature comforts. It'll be physically and mentally challenging but I'm determined to finish.
"The one thing that will get me through the cold, wet and midge bites is the thought of raising money for such a good cause."
Graeme Brown, director of Shelter Scotland, said: "I am in awe of Wayne's determination and generosity. Having just lost his home he is already thinking of how he can help others.
"At a time when funding for our vital services is under threat, people like Wayne make a real difference."
Mr Hall plans to keep a blog during his trip on Facebook to update supporters of his progress. He has set up a Just Giving page and aims to raise over £5000 for Shelter Scotland.