Allsop achieved his first adventurous milestone in 2007 when he climbed Mt Everest and, as part of his training, he completed one of the world's highest altitude marathons in Nepal last month.
He says he has a very understanding wife, Wendy, and three children, Ethan, 9, Maya, 7, and Dylan, 3.
Allsop has put the hardest leg of the "777 project" first.
"The biggest issue has been the Falklands as there's only one flight per week," he said. That meant flying in a week before and doing the marathon immediately before catching the flight out.
"I contacted the British military there and said I could talk to them about my experiences on Everest. I got a letter back from the second in command to say I'd be much better spending any extra time I had talking to a psychiatrist. However, they did invite me to talk to all of the troops."
He said he was factoring in as many "curve balls" as he could.
"Basically, I'll run on the morning of the 14th, then catch a plane to Santiago and run there before catching a flight to Los Angeles. This will be the tightest part because I land in LA at 7.50am and I have to be back on a plane to London by 4.45pm."
Then it's on to Casablanca and Hong Kong. The last run is in Auckland. He said the task would be complete in "seven days, 15 hours and 23 minutes".
Key sponsors were Air NZ, Vodafone and nutrition firm Usana.
Click here to follow Allsop's progress in real time.
