Dylan, 13, has been missing since Nov. 19, and authorities have found little information beyond what his father, Mark, has told them.
Authorities say Dylan could still be found alive. Saturday marked 20 days since Dylan was last seen.
"We are looking for Dylan," said Lieutenant Ed Phippen, a La Plata County Sheriff's Office investigator. "We are not looking for Dylan in the past tense. We want to find Dylan and return him to his family."
The search drew 263 volunteers and additional personnel from at least 17 agencies. Of dozens of items flagged by searchers, law enforcement investigators collected 10 for future reference.
It did not appear the search led to any immediate major breaks in the case.
Volunteers were organized into teams of about a dozen and sent to search along Florida Road and other county roads between Durango and Vallecito Reservoir. Some teams hiked deep into the woods near Vallecito and Lemon reservoirs. Others covered ground on horseback or ATVs.
Many of the volunteers said they were touched by the case of the missing boy who until recently attended Bayfield Middle School near here. Dylan had moved with his mother to Colorado Springs, but was visiting his father in Vallecito when the boy went missing.
Gale Caponi, a teacher at Crownpoint (Ariz.) High School, was visiting Durango when she heard authorities needed volunteers.
"I thought I needed to stay and look for this young man and hope for a finding," she said. "It's a civil responsibility."
The search was timed to beat a snow storm expected to arrive Sunday that could potentially obscure clues. Volunteers were given a handout depicting the clothing Dylan was last seen wearing: black and white basketball shorts, a black and gray "DC" T-shirt, Nike Air Jordan shoes and a Duke Blue Devils hat.
Durango marshaled its legions of recreational hikers, bringing them together on a frosty morning. They showed a seriousness of purpose as they poked at litter and bushes along Florida Road, looking for anything that might be helpful to the investigation.
"La Plata County, as you might imagine, has some incredibly skilled outdoors people," said Chris Wilbur, a civil engineer who volunteers with La Plata County Search and Rescue.
David Dea of Durango took charge of one group of volunteers, organizing them into a buddy system and making sure they would be accounted for. Dea said he was chosen to lead for his familiarity with the terrain.
"This is my hunt area," he explained.
Many volunteers said they have children near Dylan's age.
"We've got a son," said Jeff Engman. "We thought if it were our kid out here we'd like to do everything we could. It's nice to see the community come out."
People who know Dylan described him as friendly and outgoing. "He's not afraid to meet new people," said Ryan Nava, 13, a former classmate of Dylan.
Ryan's father, C.J. Nava, lives in Bayfield but works as a site scheduler for BP in Farmington. He said Dylan was a friend of their family.
"My son is 13 and was good friends with Dylan," said C.J. Nava. "He's been to our house several times. So It's been a high priority for my wife and I and my boys to bring him home."