Andrew Dickson, 59, plans to spend two months travelling from Perth in the west of the country to Brisbane in the east.
He aims to raise money for a fund set up in memory of tragic Falkirk footballer Craig Gowans.
Craig died in 2005 after being electrocuted when a 20ft long pole for nets he was carrying touched power lines.
Mr Dickson also plans to split any money raised with Radio lollipop, which provides music for children in hospital.
On his 4000-mile journey he will cross the arid Nullarbor Plain, which lies south of the scorching Great Victoria Desert.
After completing his last epic trip to raise money for Alzheimer Scotland, who helped when his wife Eileen was diagnosed with the condition at the age of just 48, Mr Dickson decided to hit the road again for a new challenge. He said: “I just felt it would be nice if some charity could raise some funding off the back off this challenge.
“Last year I did 4500 miles in two months, but I spent two weeks in Washington DC at the end because, whenever I got somewhere, I just wanted to keep cycling. I’m hoping I can do the 4000 miles in two months.”
Asked why he had chosen the Craig Gowan Foundation as a beneficiary, he said: “I lost a pal and a friend in my wife but John and Sheila lost a wee one, and I’m sure Eileen would agree that’s far worse.”
Starting out in Perth, on the south west corner of the country, Mr Dickson will cycle east towards the gold mining town of Norseman. From there he will head southwards through Adelaide and Melbourne. He will then begin heading north again, passing through the capital Canberra, Sydney and finishing in Brisbane.