The sign reads, “Caution. It is 100 miles south to the nearest town at Monson. There are no places to obtain supplies or help until Monson. Do not attempt this section unless you have a minimum of 10 days supplies and are fully equipped. This is the longest wilderness section of the entire AT and its difficulty should not be underestimated. Good hiking!”

The strong words serve as both invitation and warning to those standing at the trailhead of the Hundred-Mile Wilderness, the most isolated segment of the entire Appalachian Trail. It’s 10 days of hiking: through deep pine forests, up and down mountainous ridges, forging icy Maine streams.

At the moment, it’s where local artist Steve Ainsworth is — on the first leg of the 2,184 miles of the Appalachian Trail, the first leg of the challenge of a lifetime.

Ainsworth set out June 19 on a trip that will take him through 14 states and five and a half months of walking. According to the National Park Service, it’s 5 million adult-sized steps from one trail end in Baxter State Park, Maine, to the other at Springer Mountain, Ga.

Ainsworth began his trek in Maine, tackling the most challenging hurdle of the trail on day one: Mount Katahdin, a 5,268-foot peak and the highest elevation on the AT. On his back, he carries a 30-pound backpack with only the absolute necessities for food, shelter and communication.

“The first month will be really difficult,” said Ainsworth, days before leaving Washington. “It’s the most technically demanding part of the trail. It’s rugged terrain…a trial by fire.”

According to the Appalachian Trail Conservancy’s website, even the strongest hikers may average only one mile an hour on some parts of Maine’s AT, with areas that require grabbing onto tree roots and limbs to climb or descend that are especially slippery and hazardous in wet weather.

Ainsworth is extremely aware of the odds of completing the journey, which would put him on the ATC’s list of “2,000 milers.” Only 20- to 25-percent of those who set out to hike the trail in one shot, called a thru-hike, complete the hike. For older hikers, the reason is injury; for the younger ones, boredom, explained Ainsworth.

Physically, Ainsworth, who is in his 50s, prepared for the trip at Vidant Wellness Center, a 30-pound bag of dog food strapped to his back as he traversed simulated hills on a treadmill. Over the course of the past year, he made several trips west to hike North Carolina sections of the AT, describing one overnight on the trail last November as a good test for the journey to come: mountaintop 35 mph winds with a temperature hovering just above freezing. Later that night, it dropped to 18 degrees.

However, Ainsworth said the physical training was less daunting than preparing himself mentally for the trip.

“It’s a physical, mental and spiritual challenge,” Ainsworth said. “But bottom line, (the biggest part) is preparing mentally…being able to stay in the moment rather than looking at, ‘Oh, I have 112 more days to go.’ It’s what’s going to keep you going on the hard days.”

Testing himself physically is nothing new for Ainsworth — for many years, he ran marathons — and a thru-hike of the AT has been simmering in the back of his mind since hiking the White Mountains in his native Massachusetts as a young man, he said. He embarked on the solo journey with the full support of his wife, Dr. Debbie Ainsworth. The couple plans to reunite periodically over the next few months, meeting up where the AT emerges from the wilderness to the towns the dotting its length.

Ainsworth plans a triumphant return to Washington in mid-November. Until then, the Daily News will be checking in with the AT “south-bounder” as he makes his way from Maine to Georgia, over mountain and valley, across some of the wildest and most scenic land this country has to offer.

To follow Steve Ainsworth’s Appalachian Trail trek, visit his blog at www.trailjournals.com/2012solo.