On the first night of Alex Harrington's 6,386-mile solo bike ride to the West Coast and back, he huddled in his tiny tent, alert to every little noise outside, and wondered whether this was really such a good idea. "My first journal entry was, 'What have I got myself into?' " the Carmel teenager recalled of that evening in Rockville. Would he be safe? Would he have the legs to make it? Would his inexpensive touring bike hold up? Would he have enough time to return before leaving for college? The answer to all of those questions: Yes.

Harrington, now 19, pedaled his way across the baking-hot Plains, up the Rocky Mountains, over the Continental Divide, along the Pacific Coast, through mountainous Montana, flat Montana, across the Midwest and back to Carmel. It took him 69 days. He averaged more than 90 miles a day on his 25-pound Trek bike, which was loaded with 65 pounds of gear, food and water. He struggled in high altitudes, fought headwinds, endured 110- degree temperatures and nearly froze while camped on a mountainside ice pack. Along the way, he piled up memories and met strangers who quickly became friends. "I have realized that all over this country, there are kind, generous and wonderful people. This trip has restored my faith in humanity," Harrington wrote in an e-mail to friends after he got back. "It has been the experience of a lifetime."

It started with a daydream. In December, sitting out his last few weeks in class before graduating early from Carmel High School, Harrington began pondering options for his last summer before heading to Indiana University in Bloomington. "I was thinking of driving across the country, seeing the Pacific, seeing the West Coast thing," he recalled. "But I knew if I was driving, I knew my personality, I'd go and be done in 10 days."

An avid cyclist, he started thinking of two wheels on the open road. "It was solo all the way," he said. "That was part of the deal." He began researching a new bike and equipment he would need, what food to take, what sights he might want to see, which route to travel. After graduating, he worked to save money for the trip, figuring he'd spend about $8 to $10 a day on food. To save cash, he'd pitch his tent for free at city parks or unofficial campsites along the way.

He didn't train much. He spent four weeks visiting Europe just before he left on his bike trip. He'd only been back a week before he pedaled out of Carmel on May 23 to head west. "After one week, I was in solid shape. A 100-mile day was nothing," said Harrington, whose slight, wiry build belies powerful thighs built up from months on the road. He made it out of Indiana fairly quickly, then through Illinois. He moved on into Kansas, where he ran smack into a heat wave topping 100 degrees, which he said was "like riding into a hair dryer."

Out of water, he stopped at a gas station to get more. While standing at the counter, he passed out and awoke to a circle of strangers looking down at him. "It was only a week into the trip, and here I was, passed out on a gas station floor," Harrington said, recalling the doubts that crept into his head. He stopped at a medical facility the next day where he was counseled on the dangers of dehydration.

"Kansas is just a desolate area," he said. "In Kansas, all the towns are 30 miles apart." He rode U.S. 36 all the way to Denver. There, he inadvertently cut off another cyclist and apologized. "We got to talking, and we just hit it off right away," Harrington said. "He said, 'Why don't you come back to my house, and we'll have a cookout?' I ended up staying at his house two days." His new friends took him to a rock concert and on a hiking trip. It was the first of a half- dozen such invitations along the way, from people fascinated by what an Indiana kid was doing biking through their hometowns. They offered him shelter, fed him and drove him to bike shops when he needed minor repairs. "I never felt threatened by anyone who invited me into their home. I never ran into a single person that ever meant me harm," he said.

He pressed on, crossing the Continental Divide at 11,307 feet. "Altitude really hit me that day," he said. "I couldn't get the power in my legs I needed." There were plenty more mountains to face as he moved west. And wind. He faced three days of headwinds through Utah, with gusts up to 70 mph. A few times, while stopped along the road, gusts blasted him off his bike and knocked him down. "It exhausted me," he said. "I was so angry at the weather."

There wasn't much to look at, either. Heading over the final stretch of Utah desert and crossing into Nevada, he rode through "90 miles of absolutely nothing." He finally made California, where snow lingered in the mountains into mid-June. Six feet of snow lined the roadway at one spot. Once, he got caught up on a mountain as dusk quickly descended. He was forced to camp at the roadside -- on a snowpack 2 feet deep, his coldest night of all.

But California was also his favorite part of the trip. After hitting the coast, he rode through Redwood National Park. "It was such an awe-inspiring thing," he said. "The trees are just huge. It was a really special time. I was riding along the road looking up at the trees. I was weaving all over the road." He continued north through Oregon and Washington and crossed over to Vancouver, Canada. On the way back, skeptical U.S. Customs officials puzzled over what to do with this bedraggled kid on a loaded-down bike. They let him pass.

"I was dreading Montana," he said. "It's so big, it takes up an entire time zone. It took me a week to get through it." It went from mountainous to monotonous. More flat land was coming, through North Dakota and Minnesota, where he visited with an old friend at a summer camp. From there, it was south through Iowa and east into Illinois, accompanied by another friend who joined him for the last three days of the trip back home.

On July 30, Harrington rolled back into Carmel. Abby Cooper, a longtime friend, said she never doubted Alex would make it. "Him riding across the country doesn't surprise me at all. I knew he could do it. I knew he would do it," said Cooper, a bike shop employee who helped Harrington prepare for the trip.

His divorced parents, Dave and Polly Harrington, were supportive of the epic journey. Polly Harrington said she wasn't worried, trusting in God to keep her son safe. Regular phone calls and e-mails helped, too. She also believed her son would reach his goal. "No doubt in my mind," she said. "Once Alex sets his mind to something, he usually sees it through. He's always been very determined."