Fred Byrne's brother-in-law compiled a list of more than 70 counties between Holland, Mich., and Carter County, Mo., where Byrne's car was found, and family members plan to call law enforcement agencies and others.
Marie Hamilton, Byrne's mother-in-law, said the family wants to make sure officials in the wide area know about the case and how "they can help us search for him." Each volunteer will follow a script to cover main points, offering fliers with photos of Byrne.
Byrne, 49, has been missing since Feb. 12, when he dropped off his son at Hope College in Holland and visited his mother.
Byrne's Chevy Malibu was found parked Feb. 14 along a forest service road near Van Buren, Mo. — about 560 miles from where he was last seen. Big Rapids police said Byrne's wallet and keys were in the car.
The car might have passed through Indiana and Illinois to get to Missouri. An aerial search of Mark Twain National Forest in February didn't find Byrne.