THEIR journey will take them 3,100 miles past some of North America's most epic scenery, last just 17 days and burn in the region of 680,000 calories.
After months of preparation and training, three men from RNAS Culdrose and a firefighter from the Isles of Scilly will cycle across the USA next week to raise money for charity.
Starting in San Diego, California, on September 22, former Cornish Pirate turned paramedic Wayne Davey, Royal Marine Corporal Justin Morgan, Royal Navy Officer Lieutenant Ben Carthey and St Mary's firefighter John Williams, will cycle to Times Square in New York for October 9 – covering a staggering 182 miles a day for 17 days.
The four are hoping their challenge, which will take them through the Rocky Mountains and the iconic Monument Valley, will raise £20,000 for Children's Hospice South West, the Royal Marines Benevolent Fund and the Cornwall Air Ambulance Trust.
The toll of their task can be measured by the fact that only 2,000 people have attempted it before but that is something which Corporal Morgan, 32, who lives with his young family in Godolphin, is relishing.
He said: "We came up with the idea last year, we were talking about huge challenges where we would be able to push ourselves to the limit and cycling across a continent just seemed really appealing.
"I'm a mixed bag of excitement and nerves now. I've been dreaming about it. Last night I had a dream of cycling 180 miles in a day and woke up exhausted."
Wayne and Corporal Morgan have been planning for the idea since last August, along with original team member Damian Barnes, a fellow marine at Culdrose, who was sadly forced to drop out through injury six weeks ago.
Fortunately, the crew were able to find two willing replacements in Lieutenant Carthey and John, who each joined the team with already excellent levels of fitness.
The four have all had to fit in training around their busy work schedules – some more of a logistical challenge than others – John regularly completing 20 lap circuits of St Mary's.
Wayne, 35, who lives in Newlyn and played for the Pirates between 2000 and 2003, and 2008 and 2009, and took part in an aborted attempt to row the North Atlantic in 2008 with the 'Scilly Boys', said they are all itching to go.
He said: "It's just going to be an epic adventure. It's a good challenge and if we achieve it its something we can tell our kids about."
All the crew are aware of the obvious dangers of cycling such a great distance by road and are reliant on Royal Marine Paul 'Wheelie' A'Barrow and Harrison Ledder, a bike mechanic from sponsors Vita Cycles, who will drive their support Winnebago, which the crew will sleep in each night.
John, 42, who lives with his partner and two sons, said: "I got involved because of the actual challenge and the charity element, we see the air ambulance come in a few times a week."
Lieutenant Carthey, 31, who lives with his wife in Helston, completed an Iron Man challenge in France earlier this year.
He added: "I am just looking forward to getting out there and starting it."
For sponsorship information and to follow the group's progress on their trip visit www.3100miles.co.uk