(CNN) -- After hiking along the Amazon River for more than two years, Ed Stafford is suddenly in a rush.
The native Brit, who set out to become the first person to walk all of the river's roughly 4,000 miles more than two years ago, is hoping to finish his hike on Monday, in time to catch his scheduled flight home to Leicestershire from Brazil.
Despite collapsing from exhaustion on a roadside Sunday morning, Stafford is confident he'll make the plane.
"Feeling much better," he wrote in a blog post from northeastern Brazil on Sunday, after catching three hours of sleep. "...will walk all night from now to complete the remaining 85 kilometers."
It's the kind of fortitude that Stafford has summoned time and again since setting out from the Amazon's River source in Peru in April 2008, seeking to raise international attention about rain-forest destruction and to help raise funds to combat it.
Since then, Stafford and Gadiel "Cho" Sanchez Rivera -- a Peruvian forestry worker who joined him in July 2008 -- have encountered pit vipers, electric eels, anaconda, mosquitoes and scorpions, but very few doubts about whether they'd reach the Atlantic.
"After grabbing something to eat, and replying to emails I finally got my head down at 1:27 a.m.," Stafford wrote in a piece for CNN.com last week, after hiking for 15 straight hours. "We've never walked 55km in a day before so we are satisfied with what we've achieved, if a little stiff."
Stafford, a former British army captain, and his hiking buddy have seen their share of setbacks. Stafford contracted cutaneous leishmaniasis, a skin disease, and had to have a botfly removed from his skull. Cho suffered a nasty machete cut.
But their biggest challenges were far less dramatic.
"Although everyone would like me to say that the hardest thing has been our encounters with (indigenous residents) pointing bows and arrows at our chest, for me that wasn't the hardest part," Stafford said last month, " ... the adrenalin kicks in and you deal with exciting, potentially dangerous moments like that easily."
"It's been the mundane that had really challenged me," he said. "... The weight of the rucksack, the basic food, the constant mosquito bites, the constant thorns. The little things that in a two-day expedition wouldn't bother you have been the things that have actually been challenging."
The greatest pleasures of the journey, Stafford said, have been the warmth of the Brazilian people, with village children frequently welcoming him and Cho to new towns and their parents offering home-cooked meals.
Having never visited the Amazon before starting his expedition, Stafford now says that his quest to save the region won't end with his hike.
"I'm committed now to this place for the rest of my life," he wrote on CNN.com this month, "and I intend to take 'Walking The Amazon' around the world and keep alive the stories of the people we've met along the way, the lives in the Amazon and the tale of the jungle."
Though he says that deforestation means the Amazon "is changing faster than many of us can comprehend," Stafford has also found reasons to be hopeful about its survival while hiking.
"Although (deforestation) is sill going on in the moment," he said, "there's a generation coming through Brazil that are very aware of environmental issue and really do care about the Amazon."
As he closes in on the Amazon's mouth, Stafford has found time to nurse less lofty desires. He says the first thing he'll do after touching down in England is grab a pint of beer.
And his Peruvian partner, he says, can't wait for a pint of fresh milk.