Nigel Hearnden is taking on the 1,250-mile trek as a tribute to his wife, Anne, who died after a four-year battle with cancer.
Rome is where the couple planned to spend their 30th wedding anniversary, but Mrs Hearnden died before they reached the landmark anniversary.
Mr Hearnden, 49, said: 'Anne was an honest, warm, loving wife, mother and grandmother. Always full of life, fun and hope even when at her lowest ebb.
'I miss her so much and want to do this for her; she was a truly wonderful, courageous woman.'
Mrs Hearnden endured 20 months of chemotherapy, three major operations and beat three types of cancer.
But she died unexpectedly in November 2005 of a rapidly developing heart infection at the age of 48.
Now her husband is determined to make the trip as a tribute and donate all he raises to charities she backed. Already he is £800 towards his mammoth target and remains hopeful he will get there.
Mr Hearnden, of Beauchamp Avenue, Gosport, plans to leave next January and although some faithful friends will be joining him for stretches he plans to go most of the way alone.
The route will take him from Gosport to Portsmouth, across the channel to Caen and onward through France and Italy.
Each day will involve six hours of walking up to 15 miles with just one day off a week to rest.
He plans to arrive in Rome on May 16 – exactly three years to the day he was last there with his wife.
Mr Hearnden said: 'The response has been incredible. Everyone seems to be really supportive and I just hope it will continue. If I don't meet the target straight away I will just keep on going until I do.'