COEUR d'ALENE - Popular dentist, inventor and avid outdoorsman Dick Smart died Thursday night at home in Coeur d'Alene, surrounded by family. He was 69.

"He was incredibly wise about many things," said Charlie Nipp, of Coeur d'Alene, who has been a friend of Smart's since they were kids. "He was gentle in his approach to life, gentle in his approach to people. He was incredibly respectful of the nature that he loved so much."

The Press reported last month that Smart had an inoperable brain tumor, which he has been fighting for more than a year.

Nipp and his wife, Susan, were close friends with Smart's family. The families traveled the world together, spent time in nature hiking, camping and cross-country skiing.

"He loved this Earth and world and the people in it," said Susan Nipp. "He loved all of his patients."

She said Smart was most proud of his family. Smart and his wife, Ann, have four grown children and nine grandkids, the Nipps said.

Dick and Anne Smart's son Tom is a dentist in Coeur d'Alene, their daughter Jen is a teacher in Portland, their son Jim is a music professor at the University of Montana in Missoula and their eldest son Mike is an attorney in Virginia.

"We have been so incredibly impressed with the way the family has rallied and supported him," said Charlie Nipp. "He has a wonderful group of friends that is very broad and deep."

Smart's Railcycle, which he invented, brought him peace and joy.

Ken Wright of Coeur d'Alene, a chemistry and environmental science teacher at North Idaho College for 31 years, logged more miles than anybody with Smart on bikes that rode railroad tracks. They rode thousands of miles, he said.

"We had so many adventures in so many different places," Wright said. "They were all different and always marvelous. We often said we never had a bad trip."

They rode abandoned railroad tracks throughout the U.S., in Sweden, Norway, Patagonia and many other locations.

Wright said they loved the solitude and quiet of the remote stretches of track.

"We met fascinating people," he said.

Smart's book "Biking on Rusty Ribbons of Steel" details the adventures, and describes his love for trains and bicycles.

"He was quite philosophical," Wright said. "He had extremely keen eyes for spotting animals. He was amazing at that."

They saw plenty as they quietly passed through remote stretches of wilderness.

Wright recalled a 12-day journey through northern British Columbia, where they saw 11 black bears, spotted a fox and "chased" a moose down the track. That August 1987 journey covered 250 miles and is detailed in his book.

"We had a major trip almost every year," he said.

The two men met because Smart was Wright's dentist.

In the summer of 1981, they took their first big trip along the abandoned Milwaukee Railroad lines along the Idaho-Montana border, which later became the Route of the Hiawatha.

Smart earned a bachelor's degree from the University of Idaho and attended dental school at Marquette University. He also served in the U.S. Navy.

"He was an environmentalist or ecologist before anybody even knew what that was," said Sandy Emerson, one of Smart's friends. They met back at Coeur d'Alene High School.

"You were in junior high when you were with him," said Emerson. "He always had some adventure up his sleeve."

He recalled that Smart was a fan of John Denver music, built dioramas of old mining towns, organized a city league softball team so he could play second base - recruiting players off his dental chair to fill the roster. Emerson also recalls Smart confiscating friends' candy on camping trips.

"He was a rare individual," Emerson said. "There was a saying among some of Dick's friends: 'Dick Happens.' He was always looking for fun."

"Around here, he's a bit of hero," said Alan Brockway, development director at Heritage Health. "He founded our dental clinic."

Dental programs like it operate on tight margins, Brockway said. "They rely heavily on volunteers to get started."

He said Smart was a hero as a volunteer dentist, helping the poor with infected teeth, and also was an inspirational friend.

"Dr. Smart would say that everybody has a story," he said. "That's how he saw everyone."

In an article about Smart in 2011, Smart was quoted as saying, "I have found that some of the most interesting people are the same people living with the least."

He said that if they ever got to put pen to paper, their stories could be best-sellers.

"You have no idea who it is you're helping," Smart said in the article. "It could be someone who grows to be a future leader. It could be someone who, if shown just a little care, will take a positive outlook of their life."

• Celebration of life

A celebration of life is scheduled for 4 p.m. Wednesday, April 2, at the Lake City Community Church, at 6000 N. Ramsey Road. Plans for a reception at a separate location are underway.